使用内置的Gallery选择图片

主要使用意图Intent.ACTION_PICK,

外带一个uri:android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI

例子:

Intent intent=new Intent(Intent.ACTION_PICK,android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);

startActivityForResult(intent,requestCode);

话不多说，自己的一个简易的小Demo

源码:

import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.provider.MediaStore;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Display;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

import java.io.FileNotFoundException;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{
    private final int RESULTCODE=0;
    private Button pick;
    private ImageView imageView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        pick=(Button)findViewById(R.id.pick);
        imageView=(ImageView)findViewById(R.id.image);
        pick.setOnClickListener(this);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (resultCode == RESULT_OK && requestCode == RESULTCODE) {
            Log.i("Main","onActivity");
            //处理显示的图像
            Uri uri=data.getData();
            Display current=getWindowManager().getDefaultDisplay();
            int dw=current.getWidth();
            int dh=current.getHeight()/2-100;
            try {
                BitmapFactory.Options biops=new BitmapFactory.Options();
                biops.inJustDecodeBounds=true;
                Bitmap bmp=BitmapFactory.decodeStream(getContentResolver().openInputStream(uri),null,biops);
                int hRatio=(int)Math.ceil(biops.outHeight/(float)dh);
                int wRatio=(int)Math.ceil(biops.outWidth/(float)dw);
                if (hRatio>1 && wRatio>1) {
                    if (hRatio > wRatio) {
                        biops.inSampleSize = hRatio;
                    } else {
                        biops.inSampleSize=wRatio;
                    }
                    biops.inJustDecodeBounds=false;
                    bmp=BitmapFactory.decodeStream(getContentResolver().openInputStream(uri),null,biops);
                    imageView.setImageBitmap(bmp);
                }
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }
        }
    }
    @Override
    public void onClick(View v) {
        Intent intent=new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
        startActivityForResult(intent,RESULTCODE);
    }
}