我已经编写了与自定义相机配合使用的代码,为此我正在使用SurfaceView,现在我想知道如果我需要实现缩放功能怎么办,我从未在这种应用程序上工作过。
我用来创建自定义相机的代码如下:
MainActivity.java:
public class MainActivity extends Activity {
private SurfaceView preview=null;
private SurfaceHolder previewHolder=null;
public Camera camera ;
private boolean inPreview=false;
ImageButton btnCapture;
@SuppressWarnings("deprecation")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
preview=(SurfaceView)findViewById(R.id.surface);
previewHolder=preview.getHolder();
previewHolder.addCallback(surfaceCallback);
previewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
previewHolder.setFixedSize(getWindow().getWindowManager()
.getDefaultDisplay().getWidth(), getWindow().getWindowManager()
.getDefaultDisplay().getHeight());
btnCapture = (ImageButton) findViewById(R.id.btnCapture);
btnCapture.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(getApplicationContext(), "Capture Image(s)", Toast.LENGTH_LONG).show();
}
});
}
@Override
public void onResume() {
super.onResume();
camera=Camera.open();
}
@Override
public void onPause() {
super.onPause();
if (inPreview) {
camera.stopPreview(); }
camera.release();
camera=null;
inPreview=false;
}
private Camera.Size getBestPreviewSize(int width, int height,Camera.Parameters parameters){
Camera.Size result=null;
for (Camera.Size size : parameters.getSupportedPreviewSizes())
{
if (size.width<=width && size.height<=height)
{
if (result==null) {
result=size;
} else {
int resultArea=result.width*result.height;
int newArea=size.width*size.height;
if (newArea>resultArea) {
result=size;
}
}
}
}
return(result);
}
SurfaceHolder.Callback surfaceCallback=new SurfaceHolder.Callback(){
public void surfaceCreated(SurfaceHolder holder) {
try {
camera.setPreviewDisplay(previewHolder);
} catch (Throwable t) {
Log.e("PreviewDemo-surfaceCallback",
"Exception in setPreviewDisplay()", t);
Toast.makeText(MainActivity.this, t.getMessage(), Toast.LENGTH_LONG).show();
}
}
public void surfaceChanged(SurfaceHolder holder,int format, int width,int height) {
Camera.Parameters parameters=camera.getParameters();
Camera.Size size=getBestPreviewSize(width, height,
parameters);
if (size!=null) {
parameters.setPreviewSize(size.width, size.height);
camera.setParameters(parameters);
camera.startPreview();
inPreview=true;
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
}
};
}
activity_main.xml:-
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@drawable/splash_background" >
<android.view.SurfaceView
android:id="@+id/surface"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
<ImageButton
android:id="@+id/btnCapture"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:background="@drawable/capture"
android:contentDescription="@string/app_name" />
</RelativeLayout>