首先,我很新的android編程,所以這個錯誤可能是非常簡單的東西,我沒有注意到。但是每當我打開我的簡單應用程序時,它都會從圖像開始。當我滑動它應該改變爲一個不同的圖像,但相反,應用程序崩潰。任何想法,爲什麼這是?Android的setImageResource導致應用程序崩潰
這裏是我的Java代碼
package example.course.bananapeeler;
import android.gesture.Gesture;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.MenuItem;
import android.widget.Button;
import android.widget.TextView;
import android.widget.ImageView;
import android.view.MotionEvent;
import android.view.GestureDetector;
import android.support.v4.view.GestureDetectorCompat;
public class MainActivity extends ActionBarActivity implements GestureDetector.OnGestureListener,
GestureDetector.OnDoubleTapListener{
private ImageView mainPic;
private GestureDetectorCompat gestureDetector;
private int moneyPerSecond;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.gestureDetector = new GestureDetectorCompat(this, this);
gestureDetector.setOnDoubleTapListener(this);
//ImageView mainPic = (ImageView)findViewById(R.id.mainPic);
ImageView mainPic = (ImageView)findViewById(R.id.mainPic);
}
@Override
public boolean onSingleTapConfirmed(MotionEvent motionEvent) {
return false;
}
@Override
public boolean onDoubleTap(MotionEvent motionEvent) {
return false;
}
@Override
public boolean onDoubleTapEvent(MotionEvent motionEvent) {
return false;
}
@Override
public boolean onDown(MotionEvent motionEvent) {
return true;
}
@Override
public void onShowPress(MotionEvent motionEvent) {
}
@Override
public boolean onSingleTapUp(MotionEvent motionEvent) {
return false;
}
@Override
public boolean onScroll(MotionEvent motionEvent, MotionEvent motionEvent2, float v, float v2) {
return false;
}
@Override
public void onLongPress(MotionEvent motionEvent) {
}
@Override
public boolean onFling(MotionEvent motionEvent, MotionEvent motionEvent2, float v, float v2) {
/*
ImageView img = new ImageView(this);
findViewById(R.id.mainPic);
*/
mainPic.setImageResource(R.drawable.peeledbanana);
return true;
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onTouchEvent(MotionEvent event) {
this.gestureDetector.onTouchEvent(event);
return super.onTouchEvent(event);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
的xml文件:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity"><![CDATA[
/"peeledbanana";
android:id="@+id/imageView"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true" />
]]>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/mainPic"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true"
android:src="@drawable/mainbanana"
android:contentDescription="@string/mainPic" />
</RelativeLayout>
不知道爲什麼語法文件的格式很奇怪。這是否導致崩潰?
logcat的錯誤
05-13 17:16:47.329 2333年至2333年/ example.course.bananapeeler E/InputEventReceiver:異常分派輸入事件。 05-13 17:16:47.329 2333年至2333年/ example.course.bananapeeler E /的MessageQueue-JNI:異常中的MessageQueue回調: handleReceiveCallback 05-13 17:16:47.339
2333年至2333年/ example.course。 bananapeeler E /的MessageQueue-JNI: 顯示java.lang.NullPointerException:嘗試在example.course.bananapeeler.MainActivity.onFling空對象 參考 上調用虛擬方法 '無效 android.widget.ImageView.setImageResource(INT)' (MainActivity.java:88) at android.view.GestureDetector.onTouchEvent(GestureDetector.java:620) at android.support.v4.view.GestureDetectorCompat $ GestureDetectorCompatImplJellybeanMr2.onTouchEvent(GestureDetectorCompat.java:475) at android.support.v4.view.GestureDetectorCompat.onTouchEvent(GestureDetectorCompat.java:538) at example.course.bananapeeler.MainActivity.onTouchEvent(MainActivity.java:102) at android.app.Activity.dispatchTouchEvent(Activity。 java:2869) at android.support.v7.internal.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:59) at com.android.internal.policy.impl.PhoneWindow $ DecorView.dispatchTouchEvent(PhoneWindow.java:2529) 在android.view.View.dispatchPointerEvent(View.java:9180) 在android.view.ViewRootImpl $ ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:4734) 在android.view.ViewRootImpl $ ViewPostImeInputStage.onProcess(ViewRootImpl.java: 4572) at在android.view.ViewRootImpl $ InputStage.onDeliverToNext(ViewRootImpl.java:4149) at android.view.ViewRootImpl $ InputStage.forward(ViewRootImpl.java: 4115) 在android.view.ViewRootImpl $ AsyncInputStage.forward(ViewRootImpl.java:4229) 在android.view.ViewRootImpl $ InputStage.apply(ViewRootImpl.java:4123) 在android.view.ViewRootImpl $ AsyncInputStage.apply( ViewRootImpl.java:4286) 在android.view.ViewRootImpl $ InputStage.deliver(ViewRootImpl.java:4096) 在android.view.ViewRootImpl $ InputStage.onDeliverToNext(ViewRootImpl.java:4149) 在android.view.ViewRootImpl $ InputStage.forward(ViewRootImpl.java:4115) at android.view.View RootImpl $ InputStage.apply(ViewRootImpl.java:4123) at android.view.ViewRootImpl $ InputStage.deliver(ViewRootImpl.java:4096) at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:6600) at android。 view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:6484) at android.view.ViewRootImpl。enqueueInputEvent(ViewRootImpl.java:6455) 在android.view.ViewRootImpl $ WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:6690) 在android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:185) 在android.os.MessageQueue。 nativePollOnce(本地方法) at android.os.MessageQueue.next(MessageQueue.java:143) at android.os.Looper.loop(Looper.java:130) at android.app.ActivityThread.main(ActivityThread.java :5972) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller。運行(ZygoteInit.java:1388) at com.android.internal.os.Zygot eInit.main(ZygoteInit.java:1183)05-13 17:16:47.339 2333-2333/example.course.bananapeeler D/AndroidRuntime:關閉VM 05-13 17:16:47.339
2333-2333/example.course.bananapeeler E/AndroidRuntime:致命 EXCEPTION:main 進程:example.course.bananapeeler,PID:2333 java.lang.NullPointerException:嘗試調用虛方法void void android.widget.ImageView.setImageResource(int) 'on null object reference at example.course.bananapeeler.MainActivity.onFling(MainActivity.java:88) at android.view.GestureDetector.onTouchEvent(GestureDetector.java:620) at android.support.v4.view .GestureDetectorCompat $ GestureDetectorCompatImplJ ellybeanMr2.onTouchEvent(GestureDetectorCompat.java:475) 在android.support.v4.view.GestureDetectorCompat.onTouchEvent(GestureDetectorCompat.java:538) 在example.course.bananapeeler.MainActivity.onTouchEvent(MainActivity.java:102) 在android.app.Activity.dispatchTouchEvent(Activity.java:2869) at android.support.v7.internal.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:59) at com.android.internal.policy.impl.PhoneWindow $ DecorView.dispatchTouchEvent(PhoneWindow.java:2529) 在android.view.View.dispatchPointerEvent(View.java:9180) 在android.view.ViewRootImpl $ ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:4734) 在android.view。 ViewRootImpl $ ViewPostImeInputStage.onProcess(查看RootImpl.java:4572) at android.view.ViewRootImpl $ InputStage.deliver(ViewRootImpl.java:4096) at android.view.ViewRootImpl $ InputStage.onDeliverToNext(ViewRootImpl.java:4149) at android.view.ViewRootImpl $ InputStage.forward(ViewRootImpl.java:4115) at android.view.ViewRootImpl $ AsyncInputStage.forward(ViewRootImpl.java:4229) at android.view.ViewRootImpl $ InputStage.apply(ViewRootImpl.java:4123) at android。 view.ViewRootImpl $ AsyncInputStage.apply(ViewRootImpl.java:4286) at android.view.ViewRootImpl $ InputStage.deliver(ViewRootImpl.java:4096) at android.view.ViewRootImpl $ InputStage.onDeliverToNext(ViewRootImpl.java:4149) at android.view.ViewRootImpl $ InputStage.forward(ViewRootImpl.java:4 115) at android.view.ViewRootImpl $ InputStage.apply(ViewRootImpl.java:4123) at android.view.ViewRootImpl $ InputStage.deliver(ViewRootImpl.java:4096) at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl。 Java的:6600) 在android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:6484) 在android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:6455) 在android.view.ViewRootImpl $ WindowInputEventReceiver.onInputEvent(ViewRootImpl。的java:6690) 在android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:185) 在android.os.MessageQueue.nativePollOnce(本機方法) 在android.os.MessageQueue.next(的MessageQueue。java:143) at android.os.Looper.loop(Looper.java:130) at android.app.ActivityThread.main(ActivityThread.java:5972) 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:1388) at com.android.internal.os .ZygoteInit.main(ZygoteInit.java:1183)
你有什麼錯誤?請發佈您的logcat消息。 – AndroidEx
我添加了logcat,但我不知道如何給它正確的格式。我很抱歉,但我希望這將提供更多的信息在我的錯誤 –