本文是camera系列文章第一篇，预计三篇 ：一 拍照；二 视频；三 自定义相机
相机功能是我们最常用的，属于andorid基础能力。本文讲述一下Android如何调用相机进行录制视频。

流程

获取权限

唤醒相机

录视频并播放

一、获取权限

/**
* 所需权限数组 相机 读 写
*/
private String[] permissions = new String[]{"android.permission.CAMERA",
"android.permission.READ_EXTERNAL_STORAGE",
"android.permission.WRITE_EXTERNAL_STORAGE"};
private int takeCameraCode = 1001; // 获取全尺寸图
private int cameraCode = 10000; // 权限请求码

/**
* 申请权限
*/
private void requestPermission() {
ActivityCompat.requestPermissions(this,permissions,cameraCode);
}

/**
 * 权限处理
 * @param requestCode
 * @param permissions
 * @param grantResults
 */
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    /**
     * 权限处理
     */
    if (requestCode == cameraCode) {
        for (int i = 0; i < grantResults.length; i++) {
            if (grantResults[i] != PackageManager.PERMISSION_GRANTED) {
                requestPermission();
                return;
            }
        }
        openCamera();
    }
}

二、唤醒相机
/**
* 唤醒系统相机
*/
private void openCamera() {
Intent intent = new Intent(MediaStore.ACTION_VIDEO_CAPTURE);
if (intent.resolveActivity(getPackageManager()) != null) {
startActivityForResult(intent,takeCameraCode);
}
}

三、获取视频并播放

@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == takeCameraCode && resultCode == RESULT_OK && data != null) {
Uri videoUri = data.getData();
video.setVideoURI(videoUri);
video.start();
video.requestFocus();
}
}

本文对视频不做处理。camera写完之后，会准备写一些音视频处理的文章。

完整代码如下：

public class VideoCameraActivity extends AppCompatActivity {
/**
* 所需权限数组 相机 读 写
*/
private String[] permissions = new String[]{"android.permission.CAMERA",
"android.permission.READ_EXTERNAL_STORAGE",
"android.permission.WRITE_EXTERNAL_STORAGE"};
private int takeCameraCode = 1001; // 获取全尺寸图
private int cameraCode = 1000; // 权限请求码
private VideoView video;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_video_camera);
    video = findViewById(R.id.video);
    findViewById(R.id.open_camera).setOnClickListener(v -> {
        requestPermission();
    });
}

/**
 * 申请权限
 */
private void requestPermission() {
    ActivityCompat.requestPermissions(this,permissions,cameraCode);
}

/**
 * 权限处理
 * @param requestCode
 * @param permissions
 * @param grantResults
 */
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    /**
     * 权限处理
     */
    if (requestCode == cameraCode) {
        for (int i = 0; i < grantResults.length; i++) {
            if (grantResults[i] != PackageManager.PERMISSION_GRANTED) {
                requestPermission();
                return;
            }
        }
        openCamera();
    }
}
/**
 * 唤醒系统相机
 */
private void openCamera() {
    Intent intent = new Intent(MediaStore.ACTION_VIDEO_CAPTURE);
    if (intent.resolveActivity(getPackageManager()) != null) {
        startActivityForResult(intent,takeCameraCode);
    }
}

@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == takeCameraCode && resultCode == RESULT_OK && data != null) {
        Uri videoUri = data.getData();
        video.setVideoURI(videoUri);
        video.start();
        video.requestFocus();
    }
}

}

本文完。