我有以下代码，可让您记录屏幕上发生的事情。
它可以工作，但是会出现一些问题和无法预料的事件，我不知道哪种情况会导致该应用崩溃。
要使其中一个问题发生，步骤如下：
错误：
E/MediaRecorder: SurfaceMediaSource could not be initialized!
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.app, PID: 4465
java.lang.IllegalStateException: failed to get surface
at android.media.MediaRecorder.getSurface(Native Method)
at com.app.MainActivity2.getVirtualDisplay(MainActivity2.java:170)
at com.app.MainActivity2.startRecording(MainActivity2.java:71)
at com.app.MainActivity2.access$100(MainActivity2.java:23)
at com.app.MainActivity2$1.onClick(MainActivity2.java:47)....
清单：
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />
代码：
package com.app;
import android.content.Context;
import android.content.Intent;
import android.hardware.display.DisplayManager;
import android.hardware.display.VirtualDisplay;
import android.media.MediaRecorder;
import android.media.projection.MediaProjection;
import android.media.projection.MediaProjectionManager;
import android.os.Bundle;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import java.io.File;
import java.text.SimpleDateFormat;
import java.util.Date;
public class MainActivity2 extends AppCompatActivity {
private static final int CAST_PERMISSION_CODE = 22;
private DisplayMetrics mDisplayMetrics;
private MediaProjection mMediaProjection;
private VirtualDisplay mVirtualDisplay;
private MediaRecorder mMediaRecorder;
private MediaProjectionManager mProjectionManager;
private boolean startRec = false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
mDisplayMetrics = new DisplayMetrics();
mMediaRecorder = new MediaRecorder();
mProjectionManager = (MediaProjectionManager) getSystemService(Context.MEDIA_PROJECTION_SERVICE);
getWindowManager().getDefaultDisplay().getMetrics(mDisplayMetrics);
Button start = (Button) findViewById(R.id.start);
start.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
if (!startRec) startRecording();
}
});
Button stop = (Button) findViewById(R.id.stop);
stop.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
if (startRec) stopRecording();
}
});
}
private void startRecording() {
startRec = true;
// If mMediaProjection is null that means we didn't get a context, lets ask the user
Log.w("class:", "startRecording:start");
if (mMediaProjection == null) {
// This asks for user permissions to capture the screen
Log.w("class:", "startRecording:startResult");
startActivityForResult(mProjectionManager.createScreenCaptureIntent(), CAST_PERMISSION_CODE);
Log.w("class:", "startRecording:endResult");
return;
}
Log.w("class:", "startRecording:end");
mVirtualDisplay = getVirtualDisplay();
mMediaRecorder.start();
}
private void stopRecording() {
startRec = false;
Log.w("class:", "stopRecording:start");
if (mMediaRecorder != null) {
mMediaRecorder.stop();
mMediaRecorder.reset();
//mMediaRecorder = null;
}
if (mVirtualDisplay != null) {
mVirtualDisplay.release();
//mVirtualDisplay = null;
}
if (mMediaProjection != null) {
mMediaProjection.stop();
//mMediaProjection = null;
}
Log.w("class:", "stopRecording:end");
}
public String getCurSysDate() {
return new SimpleDateFormat("yyyy-MM-dd_HH-mm-ss").format(new Date());
}
private void prepareRecording(String name) {
if (!Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {
Toast.makeText(this, "Failed to get External Storage", Toast.LENGTH_SHORT).show();
return;
}
final String directory = Environment.getExternalStorageDirectory() + File.separator + "Recordings";
final File folder = new File(directory);
boolean success = true;
if (!folder.exists()) {
success = folder.mkdir();
}
if (!success) {
Toast.makeText(this, "Failed to create Recordings directory", Toast.LENGTH_SHORT).show();
return;
}
String videoName = (name + "_" + getCurSysDate() + ".mp4");
String filePath = directory + File.separator + videoName;
int width = mDisplayMetrics.widthPixels;
int height = mDisplayMetrics.heightPixels;
mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.SURFACE);
mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
mMediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);
mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
mMediaRecorder.setVideoEncodingBitRate(8000 * 1000);
mMediaRecorder.setVideoFrameRate(24);
mMediaRecorder.setVideoSize(width, height);
mMediaRecorder.setOutputFile(filePath);
try {
mMediaRecorder.prepare();
} catch (Exception e) {
e.printStackTrace();
return;
}
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode != CAST_PERMISSION_CODE) {
// Where did we get this request from ? -_-
Log.w("class:", "Unknown request code: " + requestCode);
return;
}
Log.w("class:", "onActivityResult:resultCode");
if (resultCode != RESULT_OK) {
startRec = false;
Toast.makeText(this, "Screen Cast Permission Denied :(", Toast.LENGTH_SHORT).show();
return;
}
prepareRecording("start");
mMediaProjection = mProjectionManager.getMediaProjection(resultCode, data);
Log.w("class:", "onActivityResult:mMediaProjection");
// TODO Register a callback that will listen onStop and release & prepare the recorder for next recording
// mMediaProjection.registerCallback(callback, null);
mVirtualDisplay = getVirtualDisplay();
mMediaRecorder.start();
}
private VirtualDisplay getVirtualDisplay() {
int screenDensity = mDisplayMetrics.densityDpi;
int width = mDisplayMetrics.widthPixels;
int height = mDisplayMetrics.heightPixels;
return mMediaProjection.createVirtualDisplay(this.getClass().getSimpleName(),
width, height, screenDensity,
DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR,
mMediaRecorder.getSurface(), null /*Callbacks*/, null /*Handler*/);
}
}
Xml：
<?xml version="1.0" encoding="utf-8"?>
<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">
<Button
android:id="@+id/start"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Start" />
<Button
android:id="@+id/stop"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Stop" />
</LinearLayout>