我制作了一个简单的录像机应用程序，其中视频开始录制按钮点击。这是我的代码：
package com.example.videocapture2;
import java.io.IOException;
import android.app.Activity;
import android.content.pm.ActivityInfo;
import android.media.CamcorderProfile;
import android.media.MediaRecorder;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.Toast;
public class MainActivity extends Activity implements SurfaceHolder.Callback,android.media.MediaRecorder.OnInfoListener{
MediaRecorder recorder;
SurfaceHolder holder;
Button Rec = null;
boolean recording = false;
int count =1;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
recorder = new MediaRecorder();
initRecorder();
setContentView(R.layout.activity_main);
SurfaceView cameraView = (SurfaceView) findViewById(R.id.videoview);
holder = cameraView.getHolder();
holder.addCallback(this);
holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
recorder.start(); //This is the line pointed to by the IllegalStateException
//cameraView.setClickable(true);
// cameraView.setOnClickListener(this);
Rec = (Button)findViewById(R.id.mybutton);
Rec.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (recording) {
recorder.stop();
recording = false;
// Let's initRecorder so we can record again
initRecorder();
prepareRecorder();
} else {
recording = true;
recorder.start();
}
}
});
}
private void initRecorder() {
recorder.setAudioSource(MediaRecorder.AudioSource.DEFAULT);
recorder.setVideoSource(MediaRecorder.VideoSource.DEFAULT);
CamcorderProfile cpHigh = CamcorderProfile
.get(CamcorderProfile.QUALITY_HIGH);
recorder.setProfile(cpHigh);
recorder.setOutputFile("/sdcard/videocapture_example"+count+".mp4");
recorder.setMaxDuration(50000); // 50 seconds
recorder.setMaxFileSize(2*1048576); // Approximately 5 megabytes
count++;
}
private void prepareRecorder() {
recorder.setPreviewDisplay(holder.getSurface());
try {
recorder.prepare();
} catch (IllegalStateException e) {
e.printStackTrace();
finish();
} catch (IOException e) {
e.printStackTrace();
finish();
}
}
public void surfaceCreated(SurfaceHolder holder) {
prepareRecorder();
}
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
}
public void surfaceDestroyed(SurfaceHolder holder) {
if (recording) {
recorder.stop();
recording = false;
}
recorder.release();
//Toast.makeText(getApplicationContext(), "Video is saved", Toast.LENGTH_LONG).show();
//finish();
}
@Override
public void onInfo(MediaRecorder mr, int what, int extra) {
// TODO Auto-generated method stub
System.out.println("Reached onInfoListener");
if(what==android.media.MediaRecorder.MEDIA_RECORDER_INFO_MAX_FILESIZE_REACHED)
{
Toast.makeText(getApplicationContext(), "Video clip recorded", Toast.LENGTH_LONG).show();
}
}
}
我应该做些什么更改才能调用
recorder.start();
来自onCreate，或者更确切地说是在我启动应用之后，而不是在OnClick方法中？此外，如果我尝试直接从OnCreate调用它，它会在recorder.start（）语句的行中抛出 IllegalStateException 。
logcat的：
04-03 12:48:51.005: E/Trace(26160): error opening trace file: No such file or directory (2)
04-03 12:48:51.025: V/ActivityThread(26160): Class path: /data/app/com.example.videocapture2-2.apk, JNI path: /data/data/com.example.videocapture2/lib
04-03 12:48:51.174: I/System.out(26160): In surface view:false
04-03 12:48:51.174: E/MediaRecorder(26160): start called in an invalid state: 4
04-03 12:48:51.175: D/AndroidRuntime(26160): Shutting down VM
04-03 12:48:51.175: W/dalvikvm(26160): threadid=1: thread exiting with uncaught exception (group=0x41bd88a8)
04-03 12:48:51.178: E/AndroidRuntime(26160): FATAL EXCEPTION: main
04-03 12:48:51.178: E/AndroidRuntime(26160): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.videocapture2/com.example.videocapture2.MainActivity}: java.lang.IllegalStateException
04-03 12:48:51.178: E/AndroidRuntime(26160): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2198)
04-03 12:48:51.178: E/AndroidRuntime(26160): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2225)
04-03 12:48:51.178: E/AndroidRuntime(26160): at android.app.ActivityThread.access$600(ActivityThread.java:151)
04-03 12:48:51.178: E/AndroidRuntime(26160): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1301)
04-03 12:48:51.178: E/AndroidRuntime(26160): at android.os.Handler.dispatchMessage(Handler.java:99)
04-03 12:48:51.178: E/AndroidRuntime(26160): at android.os.Looper.loop(Looper.java:153)
04-03 12:48:51.178: E/AndroidRuntime(26160): at android.app.ActivityThread.main(ActivityThread.java:5096)
04-03 12:48:51.178: E/AndroidRuntime(26160): at java.lang.reflect.Method.invokeNative(Native Method)
04-03 12:48:51.178: E/AndroidRuntime(26160): at java.lang.reflect.Method.invoke(Method.java:511)
04-03 12:48:51.178: E/AndroidRuntime(26160): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
04-03 12:48:51.178: E/AndroidRuntime(26160): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
04-03 12:48:51.178: E/AndroidRuntime(26160): at dalvik.system.NativeStart.main(Native Method)
04-03 12:48:51.178: E/AndroidRuntime(26160): Caused by: java.lang.IllegalStateException
04-03 12:48:51.178: E/AndroidRuntime(26160): at android.media.MediaRecorder.native_start(Native Method)
04-03 12:48:51.178: E/AndroidRuntime(26160): at android.media.MediaRecorder.start(MediaRecorder.java:728)
04-03 12:48:51.178: E/AndroidRuntime(26160): at com.example.videocapture2.MainActivity.onCreate(MainActivity.java:51)
04-03 12:48:51.178: E/AndroidRuntime(26160): at android.app.Activity.performCreate(Activity.java:5244)
04-03 12:48:51.178: E/AndroidRuntime(26160): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1082)
04-03 12:48:51.178: E/AndroidRuntime(26160): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2162)
04-03 12:48:51.178: E/AndroidRuntime(26160): ... 11 more
尝试解决此问题：
1）如果我将它保留在onCreate
中，它就不起作用2）如果我将它保存在一个从onCreate调用的新线程中，它就不起作用。
3）如果我将其保留在onClick中，并使用
模拟点击代码，它也不起作用myButton.performClick（）; 以上所有方案都会出现相同的异常错
但有趣的是，如果
recorder.start（）; 提到有保持在buttonClick事件，它工作正常。
我无法理解为什么？有人可以帮我解决这个问题吗？我需要在活动启动后立即录制和保存视频。
答案 0 :(得分：0)
因为将记录器对象加载到内存需要一些时间。所以它会显示非法状态异常。
如果你想在onCreate中使用它，请使用处理程序来延迟。
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
recorder.start();
}
}, 1000);
<强>更新
把recorder.start（）;在prepareRecorder（）方法
private void prepareRecorder() {
recorder.setPreviewDisplay(holder.getSurface());
try {
recorder.prepare();
recorder.start();
} catch (IllegalStateException e) {
e.printStackTrace();
finish();
} catch (IOException e) {
e.printStackTrace();
finish();
}
}