https://stackoverflow.com/questions/23376686
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RussianThis answer is 99% plagiarized from a Commonsware tutorial/code sample. I added a button that switches between front and back camera.
PreviewDemo.java
package com.commonsware.android.camera;
import java.io.IOException;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.hardware.Camera;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.Toast;
public class PreviewDemo extends Activity {
private static final String TAG = PreviewDemo.class.getSimpleName();
private SurfaceView preview = null;
private SurfaceHolder previewHolder = null;
private Camera camera = null;
private boolean inPreview = false;
private boolean cameraConfigured = false;
int cameraID = 0;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
preview = (SurfaceView) findViewById(R.id.preview);
previewHolder = preview.getHolder();
previewHolder.addCallback(surfaceCallback);
previewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
@SuppressLint("NewApi")
@Override
public void onResume() {
super.onResume();
// camera = Camera.open();
camera = Camera.open(cameraID);
startPreview();
}
@Override
public void onPause() {
if (inPreview) {
camera.stopPreview();
}
camera.release();
camera = null;
inPreview = false;
super.onPause();
}
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);
}
private void initPreview(int width, int height) {
if (camera != null && previewHolder.getSurface() != null) {
try {
camera.setPreviewDisplay(previewHolder);
} catch (Throwable t) {
Log.e("PreviewDemo-surfaceCallback", "Exception in setPreviewDisplay()", t);
Toast.makeText(PreviewDemo.this, t.getMessage(), Toast.LENGTH_LONG).show();
}
if (!cameraConfigured) {
Camera.Parameters parameters = camera.getParameters();
Camera.Size size = getBestPreviewSize(width, height, parameters);
if (size != null) {
parameters.setPreviewSize(size.width, size.height);
camera.setParameters(parameters);
cameraConfigured = true;
}
}
}
}
private void startPreview() {
Log.d(TAG, "start preview called");
if (cameraConfigured && camera != null) {
Log.d(TAG, "stuff works");
camera.startPreview();
inPreview = true;
}
}
SurfaceHolder.Callback surfaceCallback = new SurfaceHolder.Callback() {
public void surfaceCreated(SurfaceHolder holder) {
// no-op -- wait until surfaceChanged()
}
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
initPreview(width, height);
startPreview();
}
public void surfaceDestroyed(SurfaceHolder holder) {
// no-op
}
};
@SuppressLint("NewApi")
public void switchCamera(View view) {
Log.d(TAG, "switch called");
if (inPreview) {
camera.stopPreview();
}
camera.release();
cameraID = (cameraID + 1) % 2;
camera = Camera.open(cameraID);
try {
camera.setPreviewDisplay(previewHolder);
} catch (IOException e) {
e.printStackTrace();
}
camera.startPreview();
}
}
main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<android.view.SurfaceView
android:id="@+id/preview"
android:layout_width="match_parent"
android:layout_height="match_parent" >
</android.view.SurfaceView>
<Button
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="switch"
android:layout_alignParentBottom="true"
android:onClick="switchCamera" />
</RelativeLayout>
