我正面临 运行 时间错误和数组越界异常
I am facing run time error with Array Out of Bound exception
我的 Log Cat 错误是这样的，但我没有收到此处理程序和循环程序错误，而且我尝试了各种方法。此程序用于使用视图寻呼机自动滑动图像：
09-16 10:53:25.326 10063-10063/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.admin.myapplication, PID: 10063
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.admin.myapplication/com.example.admin.myapplication.MainActivity}: java.lang.ArrayIndexOutOfBoundsException: length=0; index=0
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2423)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2483)
at android.app.ActivityThread.access0(ActivityThread.java:153)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1349)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5438)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:738)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:628)
Caused by: java.lang.ArrayIndexOutOfBoundsException: length=0; index=0
at com.example.admin.myapplication.MainActivity.onCreate(MainActivity.java:38)
at android.app.Activity.performCreate(Activity.java:6303)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1108)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2376)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2483)
at android.app.ActivityThread.access0(ActivityThread.java:153)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1349)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5438)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:738)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:628) 09-16 10:53:25.332 10063-10063/? I/Process: Sending signal. PID: 10063 SIG: 9
我的MainActivity.class是
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
viewPager = (ViewPager) findViewById(R.id.viewPager);
slideDotspanel = (LinearLayout) findViewById(R.id.SliderDots);
ViewPagerAdapter viewPagerAdapter = new ViewPagerAdapter(this);
viewPager.setAdapter(viewPagerAdapter);
dotscount = viewPagerAdapter.getCount();
dots = new ImageView[dotscount];
for (int i = 0; i < dotscount; i++) {
dots[i] = new ImageView(this);
dots[i].setImageDrawable(ContextCompat.getDrawable(getApplicationContext(), R.drawable.unactive_dot));
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
params.setMargins(8, 0, 8, 0);
slideDotspanel.addView(dots[i], params);
}
dots[0].setImageDrawable(ContextCompat.getDrawable(getApplicationContext(), R.drawable.active_dot));
Timer timer = new Timer();
timer.scheduleAtFixedRate(new MyTimerTask(), 2000, 4000);
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
for (int i = 0; i < dotscount; i++) {
dots[i].setImageDrawable(ContextCompat.getDrawable(getApplicationContext(), R.drawable.unactive_dot
));
}
dots[position].setImageDrawable(ContextCompat.getDrawable(getApplicationContext(), R.drawable.active_dot));
}
@Override
public void onPageScrollStateChanged(int state) {
}
}
);
}
public class MyTimerTask extends TimerTask {
public void run() {
MainActivity.this.runOnUiThread(new Runnable() {
@Override
public void run() {
if (viewPager.getCurrentItem() == 0)
{
viewPager.setCurrentItem(1);
} else if (viewPager.getCurrentItem() == 1)
{
viewPager.setCurrentItem(2);
} else
viewPager.setCurrentItem(0);
}
});
}
}`
另外第38行有Array Out Of BoundException的错误-
dots[0].setImageDrawable(ContextCompat.getDrawable(getApplicationContext(), R.drawable.active_dot));
但我不明白怎么会有数组越界异常。请帮助。
非常感谢您在这件事上的时间和帮助。
问题可能来自这段代码：
ViewPagerAdapter viewPagerAdapter = new ViewPagerAdapter(this);
viewPager.setAdapter(viewPagerAdapter);
dotscount = viewPagerAdapter.getCount();
dots = new ImageView[dotscount];
您需要检查您的 ViewPagerAdapter class 是否正常工作。然后检查 viewPagerAdapter.getCount(); 是否 return 适配器项目的正确大小，因为如果您使用自动生成的代码功能，它通常是 return 0在你的 IDE 中。像这样：
@Override
public int getCount() {
return 0; // This is wrong!
}
因此，您需要 return 那里的项目大小。
我的 Log Cat 错误是这样的，但我没有收到此处理程序和循环程序错误，而且我尝试了各种方法。此程序用于使用视图寻呼机自动滑动图像：
09-16 10:53:25.326 10063-10063/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.admin.myapplication, PID: 10063
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.admin.myapplication/com.example.admin.myapplication.MainActivity}: java.lang.ArrayIndexOutOfBoundsException: length=0; index=0
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2423)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2483)
at android.app.ActivityThread.access0(ActivityThread.java:153)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1349)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5438)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:738)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:628)
Caused by: java.lang.ArrayIndexOutOfBoundsException: length=0; index=0
at com.example.admin.myapplication.MainActivity.onCreate(MainActivity.java:38)
at android.app.Activity.performCreate(Activity.java:6303)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1108)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2376)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2483)
at android.app.ActivityThread.access0(ActivityThread.java:153)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1349)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5438)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:738)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:628) 09-16 10:53:25.332 10063-10063/? I/Process: Sending signal. PID: 10063 SIG: 9
我的MainActivity.class是
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
viewPager = (ViewPager) findViewById(R.id.viewPager);
slideDotspanel = (LinearLayout) findViewById(R.id.SliderDots);
ViewPagerAdapter viewPagerAdapter = new ViewPagerAdapter(this);
viewPager.setAdapter(viewPagerAdapter);
dotscount = viewPagerAdapter.getCount();
dots = new ImageView[dotscount];
for (int i = 0; i < dotscount; i++) {
dots[i] = new ImageView(this);
dots[i].setImageDrawable(ContextCompat.getDrawable(getApplicationContext(), R.drawable.unactive_dot));
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
params.setMargins(8, 0, 8, 0);
slideDotspanel.addView(dots[i], params);
}
dots[0].setImageDrawable(ContextCompat.getDrawable(getApplicationContext(), R.drawable.active_dot));
Timer timer = new Timer();
timer.scheduleAtFixedRate(new MyTimerTask(), 2000, 4000);
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
for (int i = 0; i < dotscount; i++) {
dots[i].setImageDrawable(ContextCompat.getDrawable(getApplicationContext(), R.drawable.unactive_dot
));
}
dots[position].setImageDrawable(ContextCompat.getDrawable(getApplicationContext(), R.drawable.active_dot));
}
@Override
public void onPageScrollStateChanged(int state) {
}
}
);
}
public class MyTimerTask extends TimerTask {
public void run() {
MainActivity.this.runOnUiThread(new Runnable() {
@Override
public void run() {
if (viewPager.getCurrentItem() == 0)
{
viewPager.setCurrentItem(1);
} else if (viewPager.getCurrentItem() == 1)
{
viewPager.setCurrentItem(2);
} else
viewPager.setCurrentItem(0);
}
});
}
}`
另外第38行有Array Out Of BoundException的错误-
dots[0].setImageDrawable(ContextCompat.getDrawable(getApplicationContext(), R.drawable.active_dot));
但我不明白怎么会有数组越界异常。请帮助。
非常感谢您在这件事上的时间和帮助。
问题可能来自这段代码：
ViewPagerAdapter viewPagerAdapter = new ViewPagerAdapter(this);
viewPager.setAdapter(viewPagerAdapter);
dotscount = viewPagerAdapter.getCount();
dots = new ImageView[dotscount];
您需要检查您的 ViewPagerAdapter class 是否正常工作。然后检查 viewPagerAdapter.getCount(); 是否 return 适配器项目的正确大小，因为如果您使用自动生成的代码功能，它通常是 return 0在你的 IDE 中。像这样：
@Override
public int getCount() {
return 0; // This is wrong!
}
因此，您需要 return 那里的项目大小。