Android中通过访问本地相册或者相机设置用户头像实例

import android.content.Intent;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;
import java.io.File;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
  private Button buttonLocal, buttonCamera;
  private ImageView imageView;
  //相机拍摄的头像文件(本次演示存放在SD卡根目录下)
  private static final File USER_ICON = new File(Environment.getExternalStorageDirectory(), "user_icon.jpg");
  //请求识别码(分别为本地相册、相机、图片裁剪)
  private static final int CODE_PHOTO_REQUEST = 1;
  private static final int CODE_CAMERA_REQUEST = 2;
  private static final int CODE_PHOTO_CLIP = 3;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    buttonLocal = (Button) findViewById(R.id.buttonLocal);
    buttonCamera = (Button) findViewById(R.id.buttonCamera);
    imageView = (ImageView) findViewById(R.id.imageView);
    buttonLocal.setOnClickListener(this);
    buttonCamera.setOnClickListener(this);
  }
  //设置点击事件
  @Override
  public void onClick(View view) {
    switch (view.getId()) {
      case R.id.buttonLocal:
        //调用获取本地图片的方法
        getPicFromLocal();
        break;
      case R.id.buttonCamera:
        //调用相机拍照的方法
        getPicFromCamera();
        break;
      default:
        break;
    }
  }
  /**
   * 从本机相册获取图片
   */
  private void getPicFromLocal() {
    Intent intent = new Intent();
    // 获取本地相册方法一
    intent.setAction(Intent.ACTION_GET_CONTENT);
    intent.setType("image/*");
    //获取本地相册方法二
//    intent.setAction(Intent.ACTION_PICK);
//    intent.setDataAndType(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
//        "image/*");
    startActivityForResult(intent, CODE_PHOTO_REQUEST);
  }
  /**
   * 通过相机拍摄获取图片，
   * 并存入设置的路径中
   */
  private void getPicFromCamera() {
    Intent intent = new Intent();
    intent.setAction(MediaStore.ACTION_IMAGE_CAPTURE);
    // 下面这句指定调用相机拍照后的照片存储的路径
    intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(USER_ICON));
    startActivityForResult(intent, CODE_CAMERA_REQUEST);
  }
  /**
   * 图片裁剪
   *
   * @param uri
   */
  private void photoClip(Uri uri) {
    // 调用系统中自带的图片剪裁
    Intent intent = new Intent();
    intent.setAction("com.android.camera.action.CROP");
    intent.setDataAndType(uri, "image/*");
    // 下面这个crop=true是设置在开启的Intent中设置显示的VIEW可裁剪
    intent.putExtra("crop", "true");
    // aspectX aspectY 是宽高的比例
    intent.putExtra("aspectX", 1);
    intent.putExtra("aspectY", 1);
    /*outputX outputY 是裁剪图片宽高
     *这里仅仅是头像展示，不建议将值设置过高
     * 否则超过binder机制的缓存大小的1M限制
     * 报TransactionTooLargeException
     */
    intent.putExtra("outputX", 150);
    intent.putExtra("outputY", 150);
    intent.putExtra("return-data", true);
    startActivityForResult(intent, CODE_PHOTO_CLIP);
  }
  /**
   * 提取保存裁剪之后的图片数据，并设置头像部分的View
   */
  private void setImageToHeadView(Intent intent) {
    Bundle extras = intent.getExtras();
    if (extras != null) {
      Bitmap photo = extras.getParcelable("data");
      imageView.setImageBitmap(photo);
    }
  }
  @Override
  protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    // 用户没有进行有效的设置操作，返回
    if (resultCode == RESULT_CANCELED) {
      Toast.makeText(MainActivity.this, "取消", Toast.LENGTH_LONG).show();
      return;
    }
    switch (requestCode) {
      case CODE_CAMERA_REQUEST:
        if (USER_ICON.exists()) {
          photoClip(Uri.fromFile(USER_ICON));
        }
        break;
      case CODE_PHOTO_REQUEST:
        if (data != null) {
          photoClip(data.getData());
        }
        break;
      case CODE_PHOTO_CLIP:
        if (data != null) {
          setImageToHeadView(data);
        }
        break;
    }
    super.onActivityResult(requestCode, resultCode, data);
  }
}