Android(安卓)选取图片、手机拍照以及保存图片到本地、读取图片

在开发app中经常会遇到打开图库选取图片、手机拍照得到图片作为用户的头像。并不难，直接上代码；

content_main.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"    tools:context="com.example.administrator.camerademo.MainActivity">    <ImageView        android:id="@+id/img"        android:layout_width="100dp"        android:layout_height="100dp"        android:layout_gravity="center_horizontal"        android:src="@mipmap/ic_launcher" />    <Button        android:id="@+id/btn1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_gravity="center_horizontal"        android:text="选取图片" />    <Button        android:id="@+id/btn2"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_gravity="center_horizontal"        android:text="手机拍照" />LinearLayout>

package com.example.administrator.camerademo;import android.content.Intent;import android.graphics.Bitmap;import android.graphics.BitmapFactory;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;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;public class MainActivity extends AppCompatActivity implements View.OnClickListener {    private Button btn;    private Button btn2;    private ImageView img;    public String filePath;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.content_main);      //保存图片的路径         filePath=Environment.getExternalStorageDirectory().        getAbsolutePath()+"/a.png";        btn = (Button) findViewById(R.id.btn1);        btn2 = (Button) findViewById(R.id.btn2);        img = (ImageView) findViewById(R.id.img);        btn.setOnClickListener(this);        btn2.setOnClickListener(this);        //读取保存的位图（图片）        Bitmap bitmap1= readImg();        if(bitmap1!=null){            img.setImageBitmap(bitmap1);        }else{            return;        }    }    @Override    public void onClick(View v) {        Intent intent;        switch (v.getId()) {            case R.id.btn1:                //打开手机的图库;                intent = new Intent();                intent.setType("image/*");                intent.setAction(Intent.ACTION_GET_CONTENT);                startActivityForResult(intent, 0x1);                break;            case R.id.btn2:                intent = new Intent();                //MediaStore.ACTION_IMAGE_CAPTURE  调用系统的照相机                intent.setAction(MediaStore.ACTION_IMAGE_CAPTURE);                startActivityForResult(intent, 0x3);                break;        }    }    @Override    protected void onActivityResult(int requestCode, int resultCode, Intent data) {        if (requestCode == 0x1) {            if (data != null) {                Uri uri = data.getData();                getImg(uri);            } else {                return;            }        }        if (requestCode == 0x2) {            if (data != null) {                Bundle bundle = data.getExtras();                //得到图片                Bitmap bitmap = bundle.getParcelable("data");                //保存到图片到本地                saveImg(bitmap);                //设置图片                img.setImageBitmap(bitmap);            } else {                return;            }        }        if (requestCode == 0x3) {            if (data != null) {                Bundle bundle = data.getExtras();                Bitmap bitmap = bundle.getParcelable("data");                img.setImageBitmap(bitmap);            } else {                return;            }        }    }    //读取位图（图片）    private Bitmap readImg() {        File mfile = new File(filePath);        Bitmap bm = null;        if (mfile.exists()) {        //若该文件存在            bm = BitmapFactory.decodeFile(filePath);        }        return bm;    }    //保存图片到本地，下次直接读取    private void saveImg(Bitmap mBitmap)  {        File f = new File(filePath);        try {            //如果文件不存在，则创建文件            if(!f.exists()){                f.createNewFile();            }            //输出流            FileOutputStream out = new FileOutputStream(f);            /** mBitmap.compress 压缩图片             *             *  Bitmap.CompressFormat.PNG   图片的格式             *   100  图片的质量（0-100）             *   out  文件输出流             */            mBitmap.compress(Bitmap.CompressFormat.PNG, 100, out);            out.flush();            out.close();            Toast.makeText(this,f.getAbsolutePath().toString(),Toast.LENGTH_SHORT).show();        } catch (FileNotFoundException e) {            e.printStackTrace();        }        catch (IOException e) {            e.printStackTrace();        }    }    private void getImg(Uri uri) {        try {            InputStream inputStream = getContentResolver().openInputStream(uri);            //从输入流中解码位图            // Bitmap bitmap = BitmapFactory.decodeStream(inputStream);            //保存位图            // img.setImageBitmap(bitmap);            cutImg(uri);            //关闭流            inputStream.close();        } catch (FileNotFoundException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        }    }    //裁剪图片    private void cutImg(Uri uri) {        if (uri != null) {            Intent intent = new Intent("com.android.camera.action.CROP");            intent.setDataAndType(uri, "image/*");            //true:出现裁剪的框            intent.putExtra("crop", "true");            //裁剪宽高时的比例            intent.putExtra("aspectX", 1);            intent.putExtra("aspectY", 1);            //裁剪后的图片的大小            intent.putExtra("outputX", 300);            intent.putExtra("outputY", 300);            intent.putExtra("return-data", true);  // 返回数据            intent.putExtra("output", uri);            intent.putExtra("scale", true);            startActivityForResult(intent, 0x2);        } else {            return;        }    }}

在AndroidManifest.xml加入以下三个权限

 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> <uses-permission android:name="android.permission.CAMERA"/> <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

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