《第一行代码>，从相册取出照片时取不出来？大家看我代码有问题吗？

Question

以下是MainActivity.java的代码
package com.example.administrator.choosepictest;

import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Environment;
import android.provider.MediaStore;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;

public class MainActivity extends Activity {

public static final int TAKE_PHOTO = 1;

public static final int CROP_PHOTO = 2;

private Button takePhoto;

private ImageView picture;

private Uri imageUri;

private Button chooseFromAlbum;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    takePhoto = (Button) findViewById(R.id.take_photo);
    picture = (ImageView) findViewById(R.id.picture);
    takePhoto.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            File outputImage = new File(Environment.getExternalStorageDirectory(),"output_image.jpg");
            try{
                if(outputImage.exists()) {
                    outputImage.delete();
                }
                outputImage.createNewFile();
            }catch (IOException e) {
                e.printStackTrace();
            }
            imageUri = Uri.fromFile(outputImage);
            Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
            intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
            startActivityForResult(intent,TAKE_PHOTO);
        }
    });

    chooseFromAlbum = (Button) findViewById(R.id.choose_from_album);
    chooseFromAlbum.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            File outputImage = new File(Environment.getExternalStorageDirectory(),"output_image.jpg");
            try {
                if(outputImage.exists()) {
                    outputImage.delete();
                }
                outputImage.createNewFile();
            }catch (IOException e) {
                e.printStackTrace();
            }
            imageUri = Uri.fromFile(outputImage);
            Intent intent = new Intent("android.intent.action.GET_CONTENT");
            intent.setType("image/*");
            intent.putExtra("crop", true);
            intent.putExtra("scale",true);
            intent.putExtra(MediaStore.EXTRA_OUTPUT,imageUri);
            startActivityForResult(intent,CROP_PHOTO);
        }
    });
}

@Override
protected void onActivityResult(int requestCode,int resultCode,Intent data) {
    switch (requestCode) {
        case TAKE_PHOTO :
            if(resultCode == RESULT_OK) {
                Intent intent =new Intent ("com.android.camera.action.CROP");
                intent.setDataAndType(imageUri, "image/*");
                intent.putExtra("scale", true);
                intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
                startActivityForResult(intent,CROP_PHOTO);
            }
            break;
        case CROP_PHOTO :
            if (resultCode == RESULT_OK) {
                try {
                    Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageUri));
                    ByteArrayOutputStream baos = new ByteArrayOutputStream();
                    bitmap.compress(Bitmap.CompressFormat.JPEG, 50, baos);
                    picture.setImageBitmap(bitmap);
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                }
            }
            break;
        default:
            break;
    }
}

}

Answer 1

1.对照例子检查是否有哪句代码写错了
2.大断点debug一下，跟踪确定哪一行代码没起作用或者为空
3.参考例子：http://blog.csdn.net/gao_chun/article/details/40864121