我在尝试使图像按钮的透明区域不可点击时遇到非法异常。如何解决这个问题:我已经实现OnTouchListner
并实现了loadBitmapFromView(View v)
代码是:
package com.sunojsworkshop;
import android.os.Bundle;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ImageButton;
import android.widget.Toast;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ImageButton imgView= (ImageButton) findViewById(R.id.imageButton1);
imgView.setDrawingCacheEnabled(true);
imgView.setOnTouchListener(new OnTouchListener(){
//private final OnTouchListener changeColorListener = new OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
Bitmap bmp = loadBitmapFromView(v);
int color = bmp.getPixel((int) event.getX(),(int) event.getY());
if (color == Color.TRANSPARENT)
return false;
else {
//code to execute
Toast.makeText(MainActivity.this, "Image button is being clicked", Toast.LENGTH_SHORT).show();
return true;
}
}
public Bitmap loadBitmapFromView(View v) {
// TODO Auto-generated method stub
Bitmap b = Bitmap.createBitmap( v.getLayoutParams().width, v.getLayoutParams().height, Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(b);
v.layout(0, 0, v.getLayoutParams().width, v.getLayoutParams().height);
v.draw(c);
return b;
}
});
}
}
XML 是:
<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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:background="@drawable/worldfinal"
tools:context=".MainActivity" >
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="SELECT A DESIRED COUNTRY" />
<ImageButton
android:id="@+id/imageButton1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_below="@+id/textView1"
android:layout_marginRight="28dp"
android:layout_marginTop="93dp"
android:src="@drawable/india1"
android:background="@android:color/transparent" />
和日志是:
08-06 13:13:24.162: E/AndroidRuntime(329): FATAL EXCEPTION: main
08-06 13:13:24.162: E/AndroidRuntime(329): java.lang.IllegalArgumentException: width and height must be > 0
08-06 13:13:24.162: E/AndroidRuntime(329): at android.graphics.Bitmap.nativeCreate(Native Method)
08-06 13:13:24.162: E/AndroidRuntime(329): at android.graphics.Bitmap.createBitmap(Bitmap.java:477)
08-06 13:13:24.162: E/AndroidRuntime(329): at com.sunojsworkshop.MainActivity$1.loadBitmapFromView(MainActivity.java:49)
08-06 13:13:24.162: E/AndroidRuntime(329): at com.sunojsworkshop.MainActivity$1.onTouch(MainActivity.java:35)
08-06 13:13:24.162: E/AndroidRuntime(329): at android.view.View.dispatchTouchEvent(View.java:3881)
08-06 13:13:24.162: E/AndroidRuntime(329): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:869)
08-06 13:13:24.162: E/AndroidRuntime(329): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:869)
08-06 13:13:24.162: E/AndroidRuntime(329): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:869)
08-06 13:13:24.162: E/AndroidRuntime(329): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:869)
08-06 13:13:24.162: E/AndroidRuntime(329): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1691)
08-06 13:13:24.162: E/AndroidRuntime(329): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1125)
08-06 13:13:24.162: E/AndroidRuntime(329): at android.app.Activity.dispatchTouchEvent(Activity.java:2096)
08-06 13:13:24.162: E/AndroidRuntime(329): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1675)
08-06 13:13:24.162: E/AndroidRuntime(329): at android.view.ViewRoot.deliverPointerEvent(ViewRoot.java:2194)
08-06 13:13:24.162: E/AndroidRuntime(329): at android.view.ViewRoot.handleMessage(ViewRoot.java:1878)
08-06 13:13:24.162: E/AndroidRuntime(329): at android.os.Handler.dispatchMessage(Handler.java:99)
08-06 13:13:24.162: E/AndroidRuntime(329): at android.os.Looper.loop(Looper.java:123)
08-06 13:13:24.162: E/AndroidRuntime(329): at android.app.ActivityThread.main(ActivityThread.java:3683)
08-06 13:13:24.162: E/AndroidRuntime(329): at java.lang.reflect.Method.invokeNative(Native Method)
08-06 13:13:24.162: E/AndroidRuntime(329): at java.lang.reflect.Method.invoke(Method.java:507)
08-06 13:13:24.162: E/AndroidRuntime(329): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
08-06 13:13:24.162: E/AndroidRuntime(329): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
08-06 13:13:24.162: E/AndroidRuntime(329): at dalvik.system.NativeStart.main(Native Method)
</RelativeLayout>