Android 应用程序 - 按钮正在打开 activity 但它正在崩溃
Android App - button is opening the activity but it's crashing
我创建了一个滚动 activity，但是当我调试应用程序并单击按钮打开 activity 时，出现错误。基本上，它会使整个应用程序崩溃。但是，下面是我的代码。
是否因为它是滚动的 activity 而不是空的 activity？
这是 java 文件：
news.java
package com.example.it5.foothillers;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
public class news extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_news);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
}
}
main_acitivity.java
package com.example.it5.foothillers;
import android.app.Activity;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity implements View.OnClickListener
{
Button button;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = (Button)findViewById(R.id.button);
button.setOnClickListener(this);
}
private void buttonClick() {
startActivity(new Intent("it5.foothillers.news"));
}
@Override
public void onClick(View v) {
switch (v.getId()){
case R.id.button:
buttonClick();
break;
}
}
}
清单
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.it5.foothillers">
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".news">
<intent-filter>
<action android:name="it5.foothillers.news" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
</application>
</manifest>
日志：
03-30 12:01:49.871 2122-2122/com.example.it5.foothillers E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.it5.foothillers, PID: 2122
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.it5.foothillers/com.example.it5.foothillers.news}: java.lang.IllegalStateException: This Activity already has an action bar supplied by the window decor. Do not request Window.FEATURE_SUPPORT_ACTION_BAR and set windowActionBar to false in your theme to use a Toolbar instead.
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access0(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: java.lang.IllegalStateException: This Activity already has an action bar supplied by the window decor. Do not request Window.FEATURE_SUPPORT_ACTION_BAR and set windowActionBar to false in your theme to use a Toolbar instead.
at android.support.v7.app.AppCompatDelegateImplV7.setSupportActionBar(AppCompatDelegateImplV7.java:197)
at android.support.v7.app.AppCompatActivity.setSupportActionBar(AppCompatActivity.java:129)
at com.example.it5.foothillers.news.onCreate(news.java:17)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access0(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
开始 activity 的最简单方法是将意图更改为：
startActivity(new Intent(MainActivity.this, news.class));
堆栈跟踪显示您正在尝试添加另一个 ActionBar，而应用程序的主题已经提供了一个。
因此，您可以在清单上的 activity 声明中更改主题以不使用 ActionBar，例如：
<activity android:name=".news"
android:theme="@style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="it5.foothillers.news" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
或者您只是从 activity 代码和 activity_news.xml 中删除工具栏（因为您以后不会使用它）：
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_news);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
Intent intent=new Intent(MainActivity.this,news.class);
startActivity(intent);
Mainifest.xml
<activity android:name="com.example.it5.foothillers.news" ></activity>
This Activity already has an action bar supplied by the window decor.
您的异常消息清楚地告诉您，您已经有一个 Toolbar 作为 Activity 主题的一部分。
如果你想调用 setSupportActionBar，你应该在 styles.xml 文件中设置这样的主题。
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
你也可以只删除这两行
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
并替换为
ActionBar toolbar = getSupportActionBar();
我创建了一个滚动 activity，但是当我调试应用程序并单击按钮打开 activity 时，出现错误。基本上，它会使整个应用程序崩溃。但是，下面是我的代码。
是否因为它是滚动的 activity 而不是空的 activity？
这是 java 文件：
news.java
package com.example.it5.foothillers;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
public class news extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_news);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
}
}
main_acitivity.java
package com.example.it5.foothillers;
import android.app.Activity;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity implements View.OnClickListener
{
Button button;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = (Button)findViewById(R.id.button);
button.setOnClickListener(this);
}
private void buttonClick() {
startActivity(new Intent("it5.foothillers.news"));
}
@Override
public void onClick(View v) {
switch (v.getId()){
case R.id.button:
buttonClick();
break;
}
}
}
清单
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.it5.foothillers">
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".news">
<intent-filter>
<action android:name="it5.foothillers.news" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
</application>
</manifest>
日志：
03-30 12:01:49.871 2122-2122/com.example.it5.foothillers E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.it5.foothillers, PID: 2122
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.it5.foothillers/com.example.it5.foothillers.news}: java.lang.IllegalStateException: This Activity already has an action bar supplied by the window decor. Do not request Window.FEATURE_SUPPORT_ACTION_BAR and set windowActionBar to false in your theme to use a Toolbar instead.
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access0(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: java.lang.IllegalStateException: This Activity already has an action bar supplied by the window decor. Do not request Window.FEATURE_SUPPORT_ACTION_BAR and set windowActionBar to false in your theme to use a Toolbar instead.
at android.support.v7.app.AppCompatDelegateImplV7.setSupportActionBar(AppCompatDelegateImplV7.java:197)
at android.support.v7.app.AppCompatActivity.setSupportActionBar(AppCompatActivity.java:129)
at com.example.it5.foothillers.news.onCreate(news.java:17)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access0(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
开始 activity 的最简单方法是将意图更改为：
startActivity(new Intent(MainActivity.this, news.class));
堆栈跟踪显示您正在尝试添加另一个 ActionBar，而应用程序的主题已经提供了一个。
因此，您可以在清单上的 activity 声明中更改主题以不使用 ActionBar，例如：
<activity android:name=".news"
android:theme="@style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="it5.foothillers.news" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
或者您只是从 activity 代码和 activity_news.xml 中删除工具栏（因为您以后不会使用它）：
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_news);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
Intent intent=new Intent(MainActivity.this,news.class);
startActivity(intent);
Mainifest.xml
<activity android:name="com.example.it5.foothillers.news" ></activity>
This Activity already has an action bar supplied by the window decor.
您的异常消息清楚地告诉您，您已经有一个 Toolbar 作为 Activity 主题的一部分。
如果你想调用 setSupportActionBar，你应该在 styles.xml 文件中设置这样的主题。
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
你也可以只删除这两行
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
并替换为
ActionBar toolbar = getSupportActionBar();