Android 在导致空指针异常的活动之间切换
舱单:Android 在导致空指针异常的活动之间切换,android,nullpointerexception,android-activity,android-animation,Android,Nullpointerexception,Android Activity,Android Animation,舱单: package com.example.Lovisis; import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.view.View.OnClickListener; import
package com.example.Lovisis;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.animation.AccelerateInterpolator;
import android.view.animation.Animation;
import android.widget.Button;
import com.yashpoolla.Lovisis.R;
public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button a = (Button) findViewById(R.id.button3);
a.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
//TODO Auto-generated method stub
gotoScreen1();//startActivity(new Intent(MainActivity.this, AlarmInput.class));
}
});
Button b = (Button) findViewById(R.id.button2);
b.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
gotoScreen2();//startActivity(new Intent(MainActivity.this, Cbdata.class));
}
});
Button c = (Button) findViewById(R.id.button1);
c.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
//gotoScreen4();//startActivity(new Intent(MainActivity.this, Help.class));
}
});
Button d = (Button) findViewById(R.id.Button4);
d.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
//gotoScreen3();//startActivity(new Intent(MainActivity.this, Viewdb.class));
}
});
}
//anim start
/*public boolean onCreateOptionsMenu(Menu menu) {
boolean result = super.onCreateOptionsMenu(menu);
menu.add(0, MENU_SCREEN2, 1, R.string.menu_screen2 );
return result;
}
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
switch( id ) {
case MENU_SCREEN2:
gotoScreen2();
break;
}
return true;
}*/
private void gotoScreen1() {
View g = (View)findViewById( R.id.main);
applyRotation( g,0,90, new GotoNextActivity1());
}
private void gotoScreen2() {
View g = (View)findViewById( R.id.main);
applyRotation( g,0,90, new GotoNextActivity2());
}
private void gotoScreen3() {
View g = (View)findViewById( R.id.main);
applyRotation( g,0,90, new GotoNextActivity3());
}
private void gotoScreen4() {
View g = (View)findViewById( R.id.main);
applyRotation( g,0,90, new GotoNextActivity4());
}
public static void applyRotation(
View container,
float start,
float end,
Animation.AnimationListener animationListener ) {
// Find the center of the container
final float centerX = container.getWidth()/2.0f;
final float centerY = container.getHeight()/2.0f;
// Create a new 3D rotation with the supplied parameter
// The animation listener is used to trigger the next animation
final Rotate3dAnimation rotation =
new Rotate3dAnimation(start, end, centerX, centerY, 10.0f, true);
rotation.setDuration(500);
rotation.setFillAfter(true);
rotation.setInterpolator(new AccelerateInterpolator());
if( animationListener != null )
rotation.setAnimationListener( animationListener );
container.startAnimation(rotation);
}
private final class GotoNextActivity1 implements Animation.AnimationListener {
public void onAnimationStart(Animation animation) {
}
public void onAnimationEnd(Animation animation) {
startActivity(new Intent(MainActivity.this, AlarmInput.class));
overridePendingTransition( 0,0 );
}
public void onAnimationRepeat(Animation animation) {
}
}
private final class GotoNextActivity2 implements Animation.AnimationListener {
public void onAnimationStart(Animation animation) {
}
public void onAnimationEnd(Animation animation) {
startActivity(new Intent(MainActivity.this, Cbdata.class));
overridePendingTransition( 0,0 );
}
public void onAnimationRepeat(Animation animation) {
}
}
private final class GotoNextActivity3 implements Animation.AnimationListener {
public void onAnimationStart(Animation animation) {
}
public void onAnimationEnd(Animation animation) {
startActivity(new Intent(MainActivity.this, Viewdb.class));
overridePendingTransition( 0,0 );
}
public void onAnimationRepeat(Animation animation) {
}
}
private final class GotoNextActivity4 implements Animation.AnimationListener {
public void onAnimationStart(Animation animation) {
}
public void onAnimationEnd(Animation animation) {
startActivity(new Intent(MainActivity.this, Help.class));
overridePendingTransition( 0,0 );
}
public void onAnimationRepeat(Animation animation) {
}
}
//anim end
}
我试图在上面给出的活动中的按钮单击上切换活动,它工作正常,突然抛出空指针异常。请帮助我。只是猜测,但是
**04-17 15:14:26.599: D/AndroidRuntime(3024): Shutting down VM
04-17 15:14:26.599: W/dalvikvm(3024): threadid=1: thread exiting with uncaught exception (group=0x40018578)
04-17 15:14:26.599: E/AndroidRuntime(3024): FATAL EXCEPTION: main
04-17 15:14:26.599: E/AndroidRuntime(3024): java.lang.NullPointerException
04-17 15:14:26.599: E/AndroidRuntime(3024): at com.example.Lovisis.MainActivity.applyRotation(MainActivity.java:112)
04-17 15:14:26.599: E/AndroidRuntime(3024): at com.example.Lovisis.MainActivity.gotoScreen1(MainActivity.java:88)
04-17 15:14:26.599: E/AndroidRuntime(3024): at com.example.Lovisis.MainActivity.access$0(MainActivity.java:86)
04-17 15:14:26.599: E/AndroidRuntime(3024): at com.example.Lovisis.MainActivity$1.onClick(MainActivity.java:29)
04-17 15:14:26.599: E/AndroidRuntime(3024): at android.view.View.performClick(View.java:2485)
04-17 15:14:26.599: E/AndroidRuntime(3024): at android.view.View$PerformClick.run(View.java:9080)
04-17 15:14:26.599: E/AndroidRuntime(3024): at android.os.Handler.handleCallback(Handler.java:587)
04-17 15:14:26.599: E/AndroidRuntime(3024): at android.os.Handler.dispatchMessage(Handler.java:92)
04-17 15:14:26.599: E/AndroidRuntime(3024): at android.os.Looper.loop(Looper.java:130)
04-17 15:14:26.599: E/AndroidRuntime(3024): at android.app.ActivityThread.main(ActivityThread.java:3687)
04-17 15:14:26.599: E/AndroidRuntime(3024): at java.lang.reflect.Method.invokeNative(Native Method)
04-17 15:14:26.599: E/AndroidRuntime(3024): at java.lang.reflect.Method.invoke(Method.java:507)
04-17 15:14:26.599: E/AndroidRuntime(3024): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
04-17 15:14:26.599: E/AndroidRuntime(3024): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
04-17 15:14:26.599: E/AndroidRuntime(3024): at dalvik.system.NativeStart.main(Native Method)**
可能在将其传递到applyrotion
之前返回null
,然后返回行112
(View)findViewById( R.id.main);
将抛出NullPointerException
仔细检查id为main
的视图是否存在于所有涉及的活动中。只是猜测,但是
**04-17 15:14:26.599: D/AndroidRuntime(3024): Shutting down VM
04-17 15:14:26.599: W/dalvikvm(3024): threadid=1: thread exiting with uncaught exception (group=0x40018578)
04-17 15:14:26.599: E/AndroidRuntime(3024): FATAL EXCEPTION: main
04-17 15:14:26.599: E/AndroidRuntime(3024): java.lang.NullPointerException
04-17 15:14:26.599: E/AndroidRuntime(3024): at com.example.Lovisis.MainActivity.applyRotation(MainActivity.java:112)
04-17 15:14:26.599: E/AndroidRuntime(3024): at com.example.Lovisis.MainActivity.gotoScreen1(MainActivity.java:88)
04-17 15:14:26.599: E/AndroidRuntime(3024): at com.example.Lovisis.MainActivity.access$0(MainActivity.java:86)
04-17 15:14:26.599: E/AndroidRuntime(3024): at com.example.Lovisis.MainActivity$1.onClick(MainActivity.java:29)
04-17 15:14:26.599: E/AndroidRuntime(3024): at android.view.View.performClick(View.java:2485)
04-17 15:14:26.599: E/AndroidRuntime(3024): at android.view.View$PerformClick.run(View.java:9080)
04-17 15:14:26.599: E/AndroidRuntime(3024): at android.os.Handler.handleCallback(Handler.java:587)
04-17 15:14:26.599: E/AndroidRuntime(3024): at android.os.Handler.dispatchMessage(Handler.java:92)
04-17 15:14:26.599: E/AndroidRuntime(3024): at android.os.Looper.loop(Looper.java:130)
04-17 15:14:26.599: E/AndroidRuntime(3024): at android.app.ActivityThread.main(ActivityThread.java:3687)
04-17 15:14:26.599: E/AndroidRuntime(3024): at java.lang.reflect.Method.invokeNative(Native Method)
04-17 15:14:26.599: E/AndroidRuntime(3024): at java.lang.reflect.Method.invoke(Method.java:507)
04-17 15:14:26.599: E/AndroidRuntime(3024): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
04-17 15:14:26.599: E/AndroidRuntime(3024): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
04-17 15:14:26.599: E/AndroidRuntime(3024): at dalvik.system.NativeStart.main(Native Method)**
可能在将其传递到applyrotion
之前返回null
,然后返回行112
(View)findViewById( R.id.main);
将抛出NullPointerException
仔细检查id为
main
的视图是否存在于所有涉及的活动中。对不起,实际上我为导致空指针异常的两个布局定义了相同的名称,无论如何,感谢您的支持。对不起,实际上我为导致空指针异常的两个布局定义了相同的名称,无论如何,谢谢你的支持