安卓調用相冊和攝像頭。



package com.example.paul.invokecameraandphoto;

import android.Manifest;
import android.annotation.TargetApi;
import android.content.ContentUris;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Build;
import android.os.Environment;
import android.provider.DocumentsContract;
import android.provider.MediaStore;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v4.content.FileProvider;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;

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

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private Button mBtn;
    private Button photo;
    private ImageView mIv;
    private Uri imageuri;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mBtn= (Button) findViewById(R.id.invoke);
        photo= (Button) findViewById(R.id.photo);
        mIv= (ImageView) findViewById(R.id.lv);
        mBtn.setOnClickListener(this);
        photo.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.invoke:
                invoke();

                break;
            case R.id.photo:

                photo();

                break;

        }

    }

    private void photo() {
        if(ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE)!= PackageManager.PERMISSION_GRANTED){
            ActivityCompat.requestPermissions(MainActivity.this,new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},1);
        }else{
            openPhoto();
        }
    }

    private void openPhoto() {
        Intent i=new Intent("android.intent.action.GET_CONTENT");
        i.setType("image/*");
        startActivityForResult(i,2);

    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        switch (requestCode){
            case 1:
                if(grantResults.length>0&&grantResults[0]==PackageManager.PERMISSION_GRANTED){
                    openPhoto();
                }else{
                    Toast.makeText(this,"你需要設置權限",Toast.LENGTH_SHORT).show();
                }

                break;
        }
    }

    private void invoke() {
        File file=new File(getExternalCacheDir(),"out_image.jpg");
        if(file.exists()){
            file.delete();
        }
        try {
            file.createNewFile();
        } catch (IOException e) {
            e.printStackTrace();
        }
        if(Build.VERSION.SDK_INT>=24){
            imageuri = FileProvider.getUriForFile(MainActivity.this,"com.example.paul.invokecameraandphoto",file);
        }else{
            imageuri=Uri.fromFile(file);
        }
        Intent intent=new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        intent.putExtra(MediaStore.EXTRA_OUTPUT,imageuri);
        startActivityForResult(intent,1);

    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if(requestCode==1){
            try {
                Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageuri));
                mIv.setImageBitmap(bitmap);
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }

        }
        if(requestCode==2){
            if(Build.VERSION.SDK_INT>=19){
                handleImageOnKitKat(data);
            }else{
                handleImageBeforeKitKat(data);
            }
        }
    }
@TargetApi(19)
    private void handleImageOnKitKat(Intent data) {
        String imagePath="";
        Uri uri = data.getData();
    if(DocumentsContract.isDocumentUri(this,uri)){
        String docId=DocumentsContract.getDocumentId(uri);
        if("com.android.providers.media.dopcuments".equals(uri.getAuthority())){
            String id=docId.split(":")[1];
            String selection=MediaStore.Images.Media._ID+"="+id;
            imagePath=getImagePath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,selection);

        }else if("com.android.providers.downloads.documents".equals(uri.getAuthority())){
            Uri contentUri= ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"),Long.valueOf(docId));
            imagePath=getImagePath(contentUri,null);
        }
        displayImage(imagePath);
    }
}

    private void displayImage(String imagePath) {
        if(imagePath!=null){
            Bitmap bitmap = BitmapFactory.decodeFile(imagePath);
            mIv.setImageBitmap(bitmap);
        }
    }

    private String getImagePath(Uri externalContentUri, String selection) {
        String path=null;
        Cursor cursor=getContentResolver().query(externalContentUri,null,selection,null,null);
        if(cursor!=null){
            while (cursor.moveToNext()){
                path=cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));
            }
        }
        return  path;
    }


    private void handleImageBeforeKitKat(Intent data) {
        Uri uri = data.getData();
        String imagepath=getImagePath(uri,null);
        displayImage(imagepath);
    }
}