public class MainActivity extends AppCompatActivity {
private static final int TAKE_PHOTO = 100;
private ImageView iv; 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
super.onCreate(savedInstanceState); 
setContentView(R.layout.activity_main); 
iv = (ImageView) findViewById(R.id.iv); 
}
public void btn(View view) {
 switch (view.getId()){
  case R.id.button:
   //跳转到拍照的意图
   Intent takePhotoIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
   //判断系统中是否有照相机
   if (takePhotoIntent.resolveActivity(getPackageManager())!=null){
    startActivityForResult(takePhotoIntent,TAKE_PHOTO);
   }
   break;
 }
}
/**
 * 处理数据
 * @param requestCode
 * @param resultCode
 * @param data
 */
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
 super.onActivityResult(requestCode, resultCode, data);
 //判断请求码和返回码
 if (requestCode==TAKE_PHOTO&&resultCode==RESULT_OK){
  Bitmap bitmap = data.getParcelableExtra("data");
  iv.setImageBitmap(bitmap);
 }
}
}