构建时应用程序崩溃，但没有错误。 （记分员应用已更新）
App crashes when built, but there are no errors. (Score Keeper App updated)
我正在做 Score Keeper 应用程序，但我决定给它添加一个计时器。我查看了代码和教程如何添加一个，最后我在我的应用程序中添加了 copy/pasting 代码。似乎没有发现任何错误，但应用程序在我加载它时崩溃了，我对 Java 的有限了解使我无法找到原因！
这是我的代码（不确定所有导入的来源！）：
package com.example.android.footballscorekeeper;
import android.annotation.SuppressLint;
import android.annotation.TargetApi;
import android.app.Activity;
import android.os.Build;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.widget.Button;
import android.widget.TextView;
import android.os.CountDownTimer;
import android.view.View.OnClickListener;
import org.w3c.dom.Text;
import java.lang.annotation.Target;
import java.util.concurrent.TimeUnit;
public class MainActivity extends Activity {
int scoreHome = 0;
int scoreAway = 0;
int onTargetHome = 0;
int onTargetAway = 0;
int offTargetHome = 0;
int offTargetAway = 0;
Button startTime, stopTime, resetTime, resumeTime;
TextView timerText;
//Declare a variable to hold count down timer's paused status
private boolean isPaused = false;
//Declare a variable to hold count down timer's paused status
private boolean isCanceled = false;
//Declare a variable to hold CountDownTimer remaining time
private long timeRemaining = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
requestWindowFeature(Window.FEATURE_NO_TITLE);
startTime = (Button) findViewById(R.id.startTime);
stopTime = (Button) findViewById(R.id.stopTime);
resumeTime = (Button) findViewById(R.id.resumeTime);
resetTime = (Button) findViewById(R.id.resetTime);
timerText = (TextView) findViewById(R.id.timerText);
stopTime.setEnabled(false);
resumeTime.setEnabled(false);
resetTime.setEnabled(false);
timerText.setText("00:20:00");
//Initially disabled the pause, resume and cancel button
stopTime.setEnabled(false);
resumeTime.setEnabled(false);
resetTime.setEnabled(false);
//Set a Click Listener for start button
startTime.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
isPaused = false;
isCanceled = false;
//Disable the start and pause button
startTime.setEnabled(false);
resumeTime.setEnabled(false);
//Enabled the pause and cancel button
stopTime.setEnabled(true);
resetTime.setEnabled(true);
CountDownTimer timer;
long millisInFuture = 30000; //30 seconds
long countDownInterval = 1000; //1 second
//Initialize a new CountDownTimer instance
timer = new CountDownTimer(millisInFuture, countDownInterval) {
public void onTick(long millisUntilFinished) {
//do something in every tick
if (isPaused || isCanceled) {
//If the user request to cancel or paused the
//CountDownTimer we will cancel the current instance
cancel();
} else {
//Display the remaining seconds to app interface
//1 second = 1000 milliseconds
timerText.setText("" + millisUntilFinished / 1000);
//Put count down timer remaining time in a variable
timeRemaining = millisUntilFinished;
}
}
public void onFinish() {
//Do something when count down finished
timerText.setText("Done");
//Enable the start button
startTime.setEnabled(true);
//Disable the pause, resume and cancel button
stopTime.setEnabled(false);
resumeTime.setEnabled(false);
resetTime.setEnabled(false);
}
}.start();
}
});
//Set a Click Listener for pause button
stopTime.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
//When user request to pause the CountDownTimer
isPaused = true;
//Enable the resume and cancel button
resumeTime.setEnabled(true);
resetTime.setEnabled(true);
//Disable the start and pause button
startTime.setEnabled(false);
stopTime.setEnabled(false);
}
});
//Set a Click Listener for resume button
resumeTime.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
//Disable the start and resume button
startTime.setEnabled(false);
resumeTime.setEnabled(false);
//Enable the pause and cancel button
stopTime.setEnabled(true);
resetTime.setEnabled(true);
//Specify the current state is not paused and canceled.
isPaused = false;
isCanceled = false;
//Initialize a new CountDownTimer instance
long millisInFuture = timeRemaining;
long countDownInterval = 1000;
new CountDownTimer(millisInFuture, countDownInterval) {
public void onTick(long millisUntilFinished) {
//Do something in every tick
if (isPaused || isCanceled) {
//If user requested to pause or cancel the count down timer
cancel();
} else {
timerText.setText("" + millisUntilFinished / 1000);
//Put count down timer remaining time in a variable
timeRemaining = millisUntilFinished;
}
}
public void onFinish() {
//Do something when count down finished
timerText.setText("Done");
//Disable the pause, resume and cancel button
stopTime.setEnabled(false);
resumeTime.setEnabled(false);
resetTime.setEnabled(false);
//Enable the start button
startTime.setEnabled(true);
}
}.start();
//Set a Click Listener for cancel/stop button
resetTime.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//When user request to cancel the CountDownTimer
isCanceled = true;
//Disable the cancel, pause and resume button
stopTime.setEnabled(false);
resumeTime.setEnabled(false);
resetTime.setEnabled(false);
//Enable the start button
startTime.setEnabled(true);
//Notify the user that CountDownTimer is canceled/stopped
timerText.setText("CountDownTimer Canceled/stopped.");
}
});
}
});
//Set a Click Listener for cancel/stop button
resetTime.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//When user request to cancel the CountDownTimer
isCanceled = true;
//Disable the cancel, pause and resume button
stopTime.setEnabled(false);
resumeTime.setEnabled(false);
resetTime.setEnabled(false);
//Enable the start button
startTime.setEnabled(true);
//Notify the user that CountDownTimer is canceled/stopped
timerText.setText("CountDownTimer Canceled/stopped.");
}
});
}
public void displayScoreHome(int score) {
TextView scoreHome = (TextView) findViewById(R.id.team_a_score);
scoreHome.setText(String.valueOf(score));
}
public void displayScoreAway(int score) {
TextView scoreAway = (TextView) findViewById(R.id.team_b_score);
scoreAway.setText(String.valueOf(score));
}
public void displayOnTargetHome(int score) {
TextView onTargetHome = (TextView) findViewById(R.id.team_a_ontarget);
onTargetHome.setText(String.valueOf(score));
}
public void displayOnTargetAway(int score) {
TextView onTargetAway = (TextView) findViewById(R.id.team_b_ontarget);
onTargetAway.setText(String.valueOf(score));
}
public void displayOffTargetHome(int score) {
TextView offTargetHome = (TextView) findViewById(R.id.team_a_offtarget);
offTargetHome.setText(String.valueOf(score));
}
public void displayOffTargetAway(int score) {
TextView offTargetAway = (TextView) findViewById(R.id.team_b_offtarget);
offTargetAway.setText(String.valueOf(score));
}
public void addGoalHome(View v) {
scoreHome = scoreHome + 1;
displayScoreHome(scoreHome);
}
public void addGoalAway(View v) {
scoreAway = scoreAway + 1;
displayScoreAway(scoreAway);
}
public void addOnTargetHome(View v) {
onTargetHome = onTargetHome + 1;
displayOnTargetHome(onTargetHome);
}
public void addOnTargetAway(View v) {
onTargetAway = onTargetAway + 1;
displayOnTargetAway(onTargetAway);
}
public void addOffTargetHome(View v) {
offTargetHome = offTargetHome + 1;
displayOffTargetHome(offTargetHome);
}
public void addOffTargetAway(View v) {
offTargetAway = offTargetAway + 1;
displayOffTargetAway(offTargetAway);
}
public void resetScore(View v) {
scoreHome = 0;
scoreAway = 0;
onTargetHome = 0;
onTargetAway = 0;
offTargetHome = 0;
offTargetAway = 0;
displayScoreHome(scoreHome);
displayScoreAway(scoreAway);
displayOnTargetHome(onTargetHome);
displayOnTargetAway(onTargetAway);
displayOffTargetHome(offTargetHome);
displayOffTargetAway(offTargetAway);
}
}
这是错误日志：
07-01 13:42:49.407 21197-21197/com.example.android.footballscorekeeper
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.android.footballscorekeeper, PID: 21197
java.lang.RuntimeException: Unable to start activity
ComponentInfo{com.example.android.footballscorekeeper/com.example.android.footballscorekeeper.MainActivity}:
android.util.AndroidRuntimeException: requestFeature() must be called
before adding content
at
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3253)
at
android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3349)
at android.app.ActivityThread.access00(ActivityThread.java:221)
at
android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:7225)
at java.lang.reflect.Method.invoke(Native Method)
at
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
Caused by: android.util.AndroidRuntimeException: requestFeature() must
be called before adding content
at
com.android.internal.policy.PhoneWindow.requestFeature(PhoneWindow.java:398)
at android.app.Activity.requestWindowFeature(Activity.java:3993)
at
com.example.android.footballscorekeeper.MainActivity.onCreate(MainActivity.java:46)
at android.app.Activity.performCreate(Activity.java:6876)
at
android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1135)
at
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3206)
at
android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3349)
at android.app.ActivityThread.access00(ActivityThread.java:221)
at
android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:7225)
at java.lang.reflect.Method.invoke(Native Method)
at
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
07-01 13:43:16.977 21197-21197/com.example.android.footballscorekeeper
I/Process: Sending signal. PID: 21197 SIG: 9
正如日志告诉您的那样，您应该在调用 super.onCreate 和 setContentView 之前调用 requestWindowFeature。
@Override
protected void onCreate(Bundle savedInstanceState) {
requestWindowFeature(Window.FEATURE_NO_TITLE);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
...
}
另请参阅this question。
我正在做 Score Keeper 应用程序，但我决定给它添加一个计时器。我查看了代码和教程如何添加一个，最后我在我的应用程序中添加了 copy/pasting 代码。似乎没有发现任何错误，但应用程序在我加载它时崩溃了，我对 Java 的有限了解使我无法找到原因！
这是我的代码（不确定所有导入的来源！）：
package com.example.android.footballscorekeeper;
import android.annotation.SuppressLint;
import android.annotation.TargetApi;
import android.app.Activity;
import android.os.Build;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.widget.Button;
import android.widget.TextView;
import android.os.CountDownTimer;
import android.view.View.OnClickListener;
import org.w3c.dom.Text;
import java.lang.annotation.Target;
import java.util.concurrent.TimeUnit;
public class MainActivity extends Activity {
int scoreHome = 0;
int scoreAway = 0;
int onTargetHome = 0;
int onTargetAway = 0;
int offTargetHome = 0;
int offTargetAway = 0;
Button startTime, stopTime, resetTime, resumeTime;
TextView timerText;
//Declare a variable to hold count down timer's paused status
private boolean isPaused = false;
//Declare a variable to hold count down timer's paused status
private boolean isCanceled = false;
//Declare a variable to hold CountDownTimer remaining time
private long timeRemaining = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
requestWindowFeature(Window.FEATURE_NO_TITLE);
startTime = (Button) findViewById(R.id.startTime);
stopTime = (Button) findViewById(R.id.stopTime);
resumeTime = (Button) findViewById(R.id.resumeTime);
resetTime = (Button) findViewById(R.id.resetTime);
timerText = (TextView) findViewById(R.id.timerText);
stopTime.setEnabled(false);
resumeTime.setEnabled(false);
resetTime.setEnabled(false);
timerText.setText("00:20:00");
//Initially disabled the pause, resume and cancel button
stopTime.setEnabled(false);
resumeTime.setEnabled(false);
resetTime.setEnabled(false);
//Set a Click Listener for start button
startTime.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
isPaused = false;
isCanceled = false;
//Disable the start and pause button
startTime.setEnabled(false);
resumeTime.setEnabled(false);
//Enabled the pause and cancel button
stopTime.setEnabled(true);
resetTime.setEnabled(true);
CountDownTimer timer;
long millisInFuture = 30000; //30 seconds
long countDownInterval = 1000; //1 second
//Initialize a new CountDownTimer instance
timer = new CountDownTimer(millisInFuture, countDownInterval) {
public void onTick(long millisUntilFinished) {
//do something in every tick
if (isPaused || isCanceled) {
//If the user request to cancel or paused the
//CountDownTimer we will cancel the current instance
cancel();
} else {
//Display the remaining seconds to app interface
//1 second = 1000 milliseconds
timerText.setText("" + millisUntilFinished / 1000);
//Put count down timer remaining time in a variable
timeRemaining = millisUntilFinished;
}
}
public void onFinish() {
//Do something when count down finished
timerText.setText("Done");
//Enable the start button
startTime.setEnabled(true);
//Disable the pause, resume and cancel button
stopTime.setEnabled(false);
resumeTime.setEnabled(false);
resetTime.setEnabled(false);
}
}.start();
}
});
//Set a Click Listener for pause button
stopTime.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
//When user request to pause the CountDownTimer
isPaused = true;
//Enable the resume and cancel button
resumeTime.setEnabled(true);
resetTime.setEnabled(true);
//Disable the start and pause button
startTime.setEnabled(false);
stopTime.setEnabled(false);
}
});
//Set a Click Listener for resume button
resumeTime.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
//Disable the start and resume button
startTime.setEnabled(false);
resumeTime.setEnabled(false);
//Enable the pause and cancel button
stopTime.setEnabled(true);
resetTime.setEnabled(true);
//Specify the current state is not paused and canceled.
isPaused = false;
isCanceled = false;
//Initialize a new CountDownTimer instance
long millisInFuture = timeRemaining;
long countDownInterval = 1000;
new CountDownTimer(millisInFuture, countDownInterval) {
public void onTick(long millisUntilFinished) {
//Do something in every tick
if (isPaused || isCanceled) {
//If user requested to pause or cancel the count down timer
cancel();
} else {
timerText.setText("" + millisUntilFinished / 1000);
//Put count down timer remaining time in a variable
timeRemaining = millisUntilFinished;
}
}
public void onFinish() {
//Do something when count down finished
timerText.setText("Done");
//Disable the pause, resume and cancel button
stopTime.setEnabled(false);
resumeTime.setEnabled(false);
resetTime.setEnabled(false);
//Enable the start button
startTime.setEnabled(true);
}
}.start();
//Set a Click Listener for cancel/stop button
resetTime.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//When user request to cancel the CountDownTimer
isCanceled = true;
//Disable the cancel, pause and resume button
stopTime.setEnabled(false);
resumeTime.setEnabled(false);
resetTime.setEnabled(false);
//Enable the start button
startTime.setEnabled(true);
//Notify the user that CountDownTimer is canceled/stopped
timerText.setText("CountDownTimer Canceled/stopped.");
}
});
}
});
//Set a Click Listener for cancel/stop button
resetTime.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//When user request to cancel the CountDownTimer
isCanceled = true;
//Disable the cancel, pause and resume button
stopTime.setEnabled(false);
resumeTime.setEnabled(false);
resetTime.setEnabled(false);
//Enable the start button
startTime.setEnabled(true);
//Notify the user that CountDownTimer is canceled/stopped
timerText.setText("CountDownTimer Canceled/stopped.");
}
});
}
public void displayScoreHome(int score) {
TextView scoreHome = (TextView) findViewById(R.id.team_a_score);
scoreHome.setText(String.valueOf(score));
}
public void displayScoreAway(int score) {
TextView scoreAway = (TextView) findViewById(R.id.team_b_score);
scoreAway.setText(String.valueOf(score));
}
public void displayOnTargetHome(int score) {
TextView onTargetHome = (TextView) findViewById(R.id.team_a_ontarget);
onTargetHome.setText(String.valueOf(score));
}
public void displayOnTargetAway(int score) {
TextView onTargetAway = (TextView) findViewById(R.id.team_b_ontarget);
onTargetAway.setText(String.valueOf(score));
}
public void displayOffTargetHome(int score) {
TextView offTargetHome = (TextView) findViewById(R.id.team_a_offtarget);
offTargetHome.setText(String.valueOf(score));
}
public void displayOffTargetAway(int score) {
TextView offTargetAway = (TextView) findViewById(R.id.team_b_offtarget);
offTargetAway.setText(String.valueOf(score));
}
public void addGoalHome(View v) {
scoreHome = scoreHome + 1;
displayScoreHome(scoreHome);
}
public void addGoalAway(View v) {
scoreAway = scoreAway + 1;
displayScoreAway(scoreAway);
}
public void addOnTargetHome(View v) {
onTargetHome = onTargetHome + 1;
displayOnTargetHome(onTargetHome);
}
public void addOnTargetAway(View v) {
onTargetAway = onTargetAway + 1;
displayOnTargetAway(onTargetAway);
}
public void addOffTargetHome(View v) {
offTargetHome = offTargetHome + 1;
displayOffTargetHome(offTargetHome);
}
public void addOffTargetAway(View v) {
offTargetAway = offTargetAway + 1;
displayOffTargetAway(offTargetAway);
}
public void resetScore(View v) {
scoreHome = 0;
scoreAway = 0;
onTargetHome = 0;
onTargetAway = 0;
offTargetHome = 0;
offTargetAway = 0;
displayScoreHome(scoreHome);
displayScoreAway(scoreAway);
displayOnTargetHome(onTargetHome);
displayOnTargetAway(onTargetAway);
displayOffTargetHome(offTargetHome);
displayOffTargetAway(offTargetAway);
}
}
这是错误日志：
07-01 13:42:49.407 21197-21197/com.example.android.footballscorekeeper E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.android.footballscorekeeper, PID: 21197 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.android.footballscorekeeper/com.example.android.footballscorekeeper.MainActivity}: android.util.AndroidRuntimeException: requestFeature() must be called before adding content at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3253) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3349) at android.app.ActivityThread.access00(ActivityThread.java:221) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:158) at android.app.ActivityThread.main(ActivityThread.java:7225) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120) Caused by: android.util.AndroidRuntimeException: requestFeature() must be called before adding content at com.android.internal.policy.PhoneWindow.requestFeature(PhoneWindow.java:398) at android.app.Activity.requestWindowFeature(Activity.java:3993) at com.example.android.footballscorekeeper.MainActivity.onCreate(MainActivity.java:46) at android.app.Activity.performCreate(Activity.java:6876) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1135) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3206) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3349) at android.app.ActivityThread.access00(ActivityThread.java:221) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:158) at android.app.ActivityThread.main(ActivityThread.java:7225) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120) 07-01 13:43:16.977 21197-21197/com.example.android.footballscorekeeper I/Process: Sending signal. PID: 21197 SIG: 9
正如日志告诉您的那样，您应该在调用 super.onCreate 和 setContentView 之前调用 requestWindowFeature。
@Override
protected void onCreate(Bundle savedInstanceState) {
requestWindowFeature(Window.FEATURE_NO_TITLE);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
...
}
另请参阅this question。