我想从自定义surfaceView捕获位图图像。我尝试在imageView中设置bitmapimage
但是，surfaceView没有保存任何东西。
这是我的Android代码:
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.ImageView;
public class MainActivity extends AppCompatActivity {
OurSurface ourSurface;
FrameLayout surfaceLayout;
ImageView layoutCaptured;
Button capture;
Bitmap bitmap;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
layoutCaptured = (ImageView)findViewById(R.id.layoutCaptured);
surfaceLayout = (FrameLayout)findViewById(R.id.surfaceLayout);
capture = (Button)findViewById(R.id.capture);
capture.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
surfaceLayout.setDrawingCacheEnabled(true);
surfaceLayout.buildDrawingCache(true);
Bitmap bmp = Bitmap.createBitmap(surfaceLayout.getDrawingCache());
surfaceLayout.setDrawingCacheEnabled(false);
layoutCaptured.setImageBitmap(bmp);
Log.d("MainActivity", "onClick -> setImageBitmap");
}
});
ourSurface = new OurSurface(this);
surfaceLayout.addView(ourSurface);
}
@Override
protected void onResume() {
super.onResume();
ourSurface.resume();
}
@Override
protected void onPause() {
super.onPause();
ourSurface.pause();
}
public class OurSurface extends SurfaceView implements Runnable{
public OurSurface(Context context) {
super(context);
init(context);
}
public OurSurface(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
}
Thread thread;
SurfaceHolder holder;
boolean isItOK;
Canvas canvas;
int x1,y1,x2,y2,x3,y3;
Paint red, green, blue;
public void init(Context context){
holder = getHolder();
red = new Paint(Paint.ANTI_ALIAS_FLAG);
red.setColor(Color.RED);
red.setStyle(Paint.Style.FILL);
green = new Paint(Paint.ANTI_ALIAS_FLAG);
green.setColor(Color.GREEN);
green.setStyle(Paint.Style.FILL);
blue = new Paint(Paint.ANTI_ALIAS_FLAG);
blue.setColor(Color.BLUE);
blue.setStyle(Paint.Style.FILL);
}
public void resume(){
isItOK = true;
thread = new Thread(this);
thread.start();
}
public void pause(){
isItOK = false;
while(true){
try {
thread.join();
} catch (InterruptedException e) {
e.printStackTrace();
}
thread = null;
break;
}
}
int width, height;
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
width = w;
height = h;
Log.d("onSizeChanged", "width #"+width+", height #"+height);
bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
canvas = new Canvas(bitmap);
}
int x1Sign = 1, y1Sign = 1, x2Sign = 1, y2Sign = 1, x3Sign = 1, y3Sign = 1;
@Override
public void run() {
while(isItOK == true){
if(!holder.getSurface().isValid()){
continue;
}
canvas = holder.lockCanvas();
canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
if(x1 > width) { x1 = width; x1Sign = (-1)*x1Sign; }
else if(x1 < 0) { x1 = 0; x1Sign = (-1)*x1Sign; }
if(y1 > height) { y1 = height; y1Sign = (-1)*y1Sign; }
else if(y1 < 0) { y1 = 0; y1Sign = (-1)*y1Sign; }
if(x2 > width) { x2 = width; x2Sign = (-1)*x2Sign; }
else if(x2 < 0) { x2 = 0; x2Sign = (-1)*x2Sign; }
if(y2 > height) { y2 = height; y2Sign = (-1)*y2Sign; }
else if(y2 < 0) { y2 = 0; y2Sign = (-1)*y2Sign; }
if(x3 > width) { x3 = width; x3Sign = (-1)*x3Sign; }
else if(x3 < 0) { x3 = 0; x3Sign = (-1)*x3Sign; }
if(y3 > height) { y3 = height; y3Sign = (-1)*y3Sign; }
else if(y3 < 0) { y3 = 0; y3Sign = (-1)*y3Sign; }
x1 = x1 + 1*x1Sign;
y1 = y1 + 3*y1Sign;
x2 = x2 + 2*x2Sign;
y2 = y2 + 2*y2Sign;
x3 = x3 + 3*x3Sign;
y3 = y3 + 1*y3Sign;
canvas.drawCircle(x1, y1, 10, red);
canvas.drawCircle(x2, y2, 10, green);
canvas.drawCircle(x3, y3, 10, blue);
holder.unlockCanvasAndPost(canvas);
}
}
}
}
和activity_main.xml代码。
<LinearLayout 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"
android:orientation="vertical"
android:weightSum="2">
<LinearLayout
android:weightSum="5"
android:orientation="vertical"
android:id="@+id/mainLayout"
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="fill_parent">
<Button
android:layout_weight="1"
android:text="capture"
android:id="@+id/capture"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<ImageView
android:id="@+id/layoutCaptured"
android:layout_weight="4"
android:layout_width="match_parent"
android:layout_height="fill_parent">
</ImageView>
</LinearLayout>
<FrameLayout
android:id="@+id/surfaceLayout"
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="fill_parent">
</FrameLayout>
</LinearLayout>
请告诉我。
看起来，直接获取SurfaceView的位图是不可能的。
事实上，在某些情况下，SurfaceView的显示数据甚至不能被应用程序处理器访问——它可能是硬件视频流水线即与显示输出合成应用程序处理器通过专用视频叠加。1
在您的情况下，可以将画布绘制为位图，通常的方法是2:
- 使用bitmap . createbitmap()创建正确大小的位图
- 使用canvas (bitmap)构造函数创建一个指向这个位图的画布实例
- 绘制到画布
- 使用位图
经过一番研究后，这样做"可能"是有效的:
public Bitmap getBitmap() {
setDrawingCacheEnabled(true);
buildDrawingCache(true);
final Bitmap bitmap = Bitmap.createBitmap( getDrawingCache() );
setDrawingCacheEnabled(false);
destroyDrawingCache();
return bitmap;
}
关于它的一个项目，可以在这里找到