如何将eclipse中的图像（已存在于drawables文件中）移动到屏幕上的特定位置？ 这是我试过的代码，不要认为它甚至接近......
这看起来怎么样？
SurfaceHolder surfaceHolder;
SurfaceView surface = new SurfaceView(this);
Rect rect = new Rect(0,0,100,100);
这是在onCreate
LinearLayout layout = (LinearLayout) findViewById(R.layout.activity_test2);
surfaceHolder = surface.getHolder();
layout.addView(surface);
（公众观点在我的主要活动中）
public void onDraw(Canvas canvas) {
canvas = surfaceHolder.lockCanvas();
Bitmap image1 = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
canvas.drawBitmap(image1, null, rect, null);
surfaceHolder.unlockCanvasAndPost(canvas);
}
logcat的
02-15 01:42:16.824: W/Trace(2782): Unexpected value from nativeGetEnabledTags: 0
02-15 01:42:16.824: W/Trace(2782): Unexpected value from nativeGetEnabledTags: 0
02-15 01:42:49.993: W/Trace(2782): Unexpected value from nativeGetEnabledTags: 0
02-15 01:43:03.026: W/Trace(2992): Unexpected value from nativeGetEnabledTags: 0
02-15 01:43:03.026: W/Trace(2992): Unexpected value from nativeGetEnabledTags: 0
02-15 01:43:03.026: W/Trace(2992): Unexpected value from nativeGetEnabledTags: 0
02-15 01:43:03.474: W/Trace(2992): Unexpected value from nativeGetEnabledTags: 0
02-15 01:43:03.505: W/Trace(2992): Unexpected value from nativeGetEnabledTags: 0
02-15 01:43:03.544: D/AndroidRuntime(2992): Shutting down VM
02-15 01:43:03.544: W/dalvikvm(2992): threadid=1: thread exiting with uncaught exception (group=0x40a70930)
02-15 01:43:03.733: E/AndroidRuntime(2992): FATAL EXCEPTION: main
02-15 01:43:03.733: E/AndroidRuntime(2992): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.test2/com.example.test2.Test2}: java.lang.NullPointerException
02-15 01:43:03.733: E/AndroidRuntime(2992): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2106)
02-15 01:43:03.733: E/AndroidRuntime(2992): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
02-15 01:43:03.733: E/AndroidRuntime(2992): at android.app.ActivityThread.access$600(ActivityThread.java:141)
02-15 01:43:03.733: E/AndroidRuntime(2992): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
02-15 01:43:03.733: E/AndroidRuntime(2992): at android.os.Handler.dispatchMessage(Handler.java:99)
02-15 01:43:03.733: E/AndroidRuntime(2992): at android.os.Looper.loop(Looper.java:137)
02-15 01:43:03.733: E/AndroidRuntime(2992): at android.app.ActivityThread.main(ActivityThread.java:5039)
02-15 01:43:03.733: E/AndroidRuntime(2992): at java.lang.reflect.Method.invokeNative(Native Method)
02-15 01:43:03.733: E/AndroidRuntime(2992): at java.lang.reflect.Method.invoke(Method.java:511)
02-15 01:43:03.733: E/AndroidRuntime(2992): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
02-15 01:43:03.733: E/AndroidRuntime(2992): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
02-15 01:43:03.733: E/AndroidRuntime(2992): at dalvik.system.NativeStart.main(Native Method)
02-15 01:43:03.733: E/AndroidRuntime(2992): Caused by: java.lang.NullPointerException
02-15 01:43:03.733: E/AndroidRuntime(2992): at android.content.ContextWrapper.getResources(ContextWrapper.java:89)
02-15 01:43:03.733: E/AndroidRuntime(2992): at android.view.ContextThemeWrapper.getResources(ContextThemeWrapper.java:78)
02-15 01:43:03.733: E/AndroidRuntime(2992): at android.view.View.<init>(View.java:3224)
02-15 01:43:03.733: E/AndroidRuntime(2992): at android.view.SurfaceView.<init>(SurfaceView.java:181)
02-15 01:43:03.733: E/AndroidRuntime(2992): at com.example.test2.Test2.<init>(Test2.java:44)
02-15 01:43:03.733: E/AndroidRuntime(2992): at java.lang.Class.newInstanceImpl(Native Method)
02-15 01:43:03.733: E/AndroidRuntime(2992): at java.lang.Class.newInstance(Class.java:1319)
02-15 01:43:03.733: E/AndroidRuntime(2992): at android.app.Instrumentation.newActivity(Instrumentation.java:1054)
02-15 01:43:03.733: E/AndroidRuntime(2992): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2097)
02-15 01:43:03.733: E/AndroidRuntime(2992): ... 11 more
02-15 01:43:11.183: I/Process(2992): Sending signal. PID: 2992 SIG: 9
答案 0 :(得分：0)
您需要使用SurfaceView来保存画布。就像任何其他视图一样，您可以设置LayoutParams。
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/LinearLayout1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity" >
<LinearLayout
android:id="@+id/myLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
</LinearLayout>
</LinearLayout>
package com.sample.androidcrashtest;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.widget.LinearLayout;
import android.widget.FrameLayout.LayoutParams;
public class MainActivity extends Activity{
Canvas canvas; //Your canvas to draw on
LinearLayout myLayout; //The layout that holds the surfaceview
SurfaceView surface;
SurfaceHolder surfaceHolder;
public void onCreate(Bundle bundle) {
super.onCreate(bundle);
setContentView(R.layout.activity_main);
myLayout = (LinearLayout) findViewById(R.id.myLayout);
LinearLayout.LayoutParams params_surfaceCanvas = new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
surface = new SurfaceView(this);
surface.setLayoutParams(params_surfaceCanvas);
//Assign a surfaceholder to the surface
surfaceHolder = surface.getHolder();
myLayout.addView(surface);
canvas = new Canvas();
//Call on draw method
onDraw();
}
public void onDraw() {
//Starts a thread
new Thread(new Runnable() {
public void run() {
while(true) {
//Loops until surfaceHolder is valid to use
if (surfaceHolder.getSurface().isValid()) {
Log.i("Drawing","Drawing");
//Always lock the canvas if you want to draw in surfaceview
canvas = surfaceHolder.lockCanvas();
Bitmap image1 = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
canvas.drawColor(Color.WHITE); //The background color of the canvas
canvas.drawBitmap(image1, 100, 100, null);
//Don't forget to unlock it after you draw in the surfaceview
surfaceHolder.unlockCanvasAndPost(canvas);
//breaks the while and end the thread.
break;
}
}
}
}).start();
}
}