Question

Android code to keep recording a video and should save only last 10minutes of the video in the sd card?

我的代码正在录制并保存sd卡内的视频但是在相机关闭后我收到强制关闭消息的错误。当我使用camera.open（），camera.release（）和相机时.unlock（）方法我收到一个未定义的错误。我的代码如下： package com.example.myapp2;

import java.io.File;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;

import android.app.Activity;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Camera;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;
import android.widget.VideoView;

public class MainActivity extends Activity {
    // Activity request codes
    private static final int CAMERA_CAPTURE_VIDEO_REQUEST_CODE = 200;
    public static final int MEDIA_TYPE_VIDEO = 2;
    // directory name to store captured images and videos
    private static final String VIDEO_DIRECTORY_NAME = "Hello Camera";
    private Uri fileUri; // file url to store image/video
    // VideoView videoPreview;
    Button preview,buttonRecordVideo;
    Camera camera;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);  
        buttonRecordVideo = (Button) findViewById(R.id.btnRecordVideo);  
       /**
         * Record video button click event
         */        
        buttonRecordVideo.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // record video
                recordVideo();
            }
        });
        // Checking camera availability
        if (!isDeviceSupportCamera()) {
            Toast.makeText(getApplicationContext(),
                    "Sorry! Your device doesn't support camera",
                    Toast.LENGTH_LONG).show();
            // will close the app if the device does't have camera
            finish();
        }
    }

   /*
     * Checking device has camera hardware or not
     */
    private boolean isDeviceSupportCamera() {
        if (getApplicationContext().getPackageManager().hasSystemFeature(
                PackageManager.FEATURE_CAMERA)) {
            // this device has a camera
            return true;
        } else {
            // no camera on this device
            return false;
        }
    }

    /**
     * Here we store the file url as it will be null after returning from camera
     * app
     */
    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);

        // save file url in bundle as it will be null on scren orientation
        // changes
        outState.putParcelable("file_uri", fileUri);
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);

        // get the file url
        fileUri = savedInstanceState.getParcelable("file_uri");
    }

    /**
     * Recording video
     */
    private void recordVideo() {
        Intent intent = new Intent(MediaStore.ACTION_VIDEO_CAPTURE);

        fileUri = getOutputMediaFileUri(MEDIA_TYPE_VIDEO);

        // set video quality
        intent.putExtra(MediaStore.EXTRA_VIDEO_QUALITY, 1);

        intent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri); // set the image file
                                                            // name
        intent.putExtra(MediaStore.EXTRA_DURATION_LIMIT, 6); //restricting video by time limit(seconds)
        // intent.putExtra(MediaStore.EXTRA_SIZE_LIMIT,1317961L); //restricting video by using memory size(BYTES)
        // start the video capture Intent
        startActivityForResult(intent, CAMERA_CAPTURE_VIDEO_REQUEST_CODE);
    }

    /**
     * Receiving activity result method will be called after closing the camera
     * */

    @Override 
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        // if the result is capturing Image
       if (requestCode == CAMERA_CAPTURE_VIDEO_REQUEST_CODE) {
            if (resultCode == RESULT_OK) {
                // video successfully recorded
                // preview the recorded video
                release();
               // previewVideo();
            } else if (resultCode == RESULT_CANCELED) {
                // user cancelled recording
                Toast.makeText(getApplicationContext(),
                        "User cancelled video recording", Toast.LENGTH_SHORT)
                        .show();

            } else {
                // failed to record video
                Toast.makeText(getApplicationContext(),
                        "Sorry! Failed to record video", Toast.LENGTH_SHORT)
                        .show();
            }
        }
    } 

    public final void release()
    {
        camera.save();
    }


    /**
     * ------------ Helper Methods ----------------------
     * */

    /**
     * Creating file uri to store image/video
     */
    public Uri getOutputMediaFileUri(int type) {
        return Uri.fromFile(getOutputMediaFile(type));
    }

    /**
     * returning image / video
     */
    private static File getOutputMediaFile(int type) {

        // External sdcard location
        File mediaStorageDir = new File(
                Environment
                        .getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),
                VIDEO_DIRECTORY_NAME);

        // Create the storage directory if it does not exist
        if (!mediaStorageDir.exists()) {
            if (!mediaStorageDir.mkdirs()) {
                Log.d(VIDEO_DIRECTORY_NAME, "Oops! Failed create "
                        + VIDEO_DIRECTORY_NAME + " directory");
                return null;
            }
        }

        // Create a media file name
        String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss",
                Locale.getDefault()).format(new Date());
        File mediaFile;
        if (type == MEDIA_TYPE_VIDEO) {
            mediaFile = new File(mediaStorageDir.getPath() + File.separator
                    + "VID_" + timeStamp + ".mp4");
        } else {
            return null;
        }

        return mediaFile;
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }

}

Answer 1

在你的代码中，你已经声明了一个类级别变量Camera camera，但你根本没有在任何地方使用它，事实上你甚至没有初始化它，所以它在你的代码中保持为null，因此例外。

您正在做的是，使用意图录制视频。如果要创建自定义视频录像机，请选中this documentation here by developers.android.com。它为您的问题（带代码）

提供了非常好的详细解决方案

如果这可以解决您的问题，请将此标记为已接受的答案。：）

用于记录视频的android代码，应该只保存sd卡中视频的最后10分钟

1 个答案: