涉及到的内容 ：

1、图片剪切，2、图片保存到SD卡 3、文件读取和保存 4、自定义View 绘制平滑曲线
5、RecycleView 显示 6、Glide框架显示图片 7、大图片显示 8、从相册选择图片

所用设备：

三星 华为 平板

目录结构

目录结构

Utils封装

1.权限检查

 

import android.Manifest;
import android.app.Activity;
import android.content.Context;
import android.content.pm.PackageManager;
import android.os.Build;
import android.support.v4.app.ActivityCompat;
import android.util.Log;

public class CheckPermissionsUtil {
    private static final String TAG = " fuck";
    Context mContext;

    public CheckPermissionsUtil(Context mContext) {
        this.mContext = mContext;
    }
    private String[] needPermissions = {
            Manifest.permission.READ_EXTERNAL_STORAGE,
            Manifest.permission.MOUNT_UNMOUNT_FILESYSTEMS,
            Manifest.permission.WRITE_EXTERNAL_STORAGE

    };

    private boolean checkPermission(String... needPermissions) {
        for (String permission : needPermissions) {
            if (ActivityCompat.checkSelfPermission(mContext, permission) != PackageManager.PERMISSION_GRANTED) {
                return false;
            }
        }
        return true;
    }

    private void requestPermission(Activity activity, int code, String... needPermissions) {
        ActivityCompat.requestPermissions(activity, needPermissions, code);
        Log.i(TAG, "request Permission...");
    }
    public void requestAllPermission(Activity activity) {
        if (Build.VERSION.SDK_INT >= 23) {
            Log.i(TAG, "request All Permission...");
            for (String permission : needPermissions) {
                if (!checkPermission(permission)) {
                    requestPermission(activity, 0, permission);
                }
            }
        }
    }
}

调用流程

     CheckPermissionsUtil checkPermissionsUtil = new CheckPermissionsUtil(this);
     checkPermissionsUtil.requestAllPermission(this);

2.调用系统图片剪切

import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.net.Uri;

/**
 * Created by Administrator on 2017/5/5 0005.
 * 图片裁剪
 */

public class CutUitl {


    public static Uri Ucrop(Uri uri, Activity activity) {
        // 裁剪图片
        Intent intent = new Intent("com.android.camera.action.CROP");
        intent.setDataAndType(uri, "image/*");
        intent.putExtra("crop", "true");
        intent.putExtra("aspectX", 800);
        intent.putExtra("aspectY", 1000);

        intent.putExtra("scale", true);
        intent.putExtra("return-data", true);
        intent.putExtra(MediaStore.EXTRA_OUTPUT, uri);
        intent.putExtra("outputFormat", Bitmap.CompressFormat.JPEG.toString());
        intent.putExtra("FaceDetection", true); //  face detection
        activity.startActivityForResult(intent, 200);

        return uri;
    }


    public static void UcropNoUri(Uri uri, Activity activity) {
        // 裁剪图片
        if(null == uri){
            return;
        }

        Intent intent = new Intent();
        intent.setAction("com.android.camera.action.CROP");
        intent.setDataAndType(uri, "image/*");// mUri是已经选择的图片Uri
        intent.putExtra("crop", "true");
        intent.putExtra("aspectX", 800);
        intent.putExtra("aspectY", 1000);
        intent.putExtra("scale", true);
        intent.putExtra("return-data", true);
        activity.startActivityForResult(intent, 200);


    }

}

3.文件读取和存储

import android.content.Context;
import android.graphics.Bitmap;
import android.os.Environment;
import android.text.TextUtils;
import android.util.Log;
import android.widget.Toast;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.RandomAccessFile;

import cn.forward.androids.utils.ImageUtils;

/**
 * 文件读取和保存
 */

public class FileUtil {

    /*存储过的文件名路径*/
    private static String SAVEPATH = "/sdcard/DCIM/savealva/";
    private static final String SAVEFILENAME = "save.txt";
    /*存储对应坐标和文件*/
    private static String PATH = "/sdcard/DCIM/alva/";

    private static final String TAG = "zhangxin";
    private static String strContent;

    private static File files = null;
    private static File file = null;
    private static String strFilePath;



    public static void writeTxtToFile(String strcontent,String name,String path) {


            //生成文件夹之后，再生成文件，不然会出错
            makeFilePath(path, name);
            strFilePath = path + name;
        // 每次写入时，都换行写
        strContent = strcontent + "\r\n";
        try {
            File file = new File(strFilePath);
            if (!file.exists()) {
                Log.e(TAG, "输出信息-->: " + strFilePath);
                file.getParentFile().mkdirs();
                file.createNewFile();
            }
            RandomAccessFile raf = new RandomAccessFile(file, "rwd");
            raf.seek(file.length());
            raf.write(strContent.getBytes());

            raf.close();

        } catch (Exception e) {
            Log.e(TAG, "输出信息-->: " + e.getMessage());
        }
    }

    /**
     * @param fileName
     * @return
     * @throws IOException
     * @desc 读取sd卡文件内容
     */
    public static String readSDCard(String fileName) throws IOException {
        // File file = new File(Environment.getExternalStorageDirectory(),fileName);
        File file = new File(fileName);
        FileInputStream fis = new FileInputStream(file);
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        int len = 0;
        while ((len = fis.read(buffer)) != -1) {
            bos.write(buffer, 0, len);
        }
        byte[] data = bos.toByteArray();
        fis.close();
        bos.close();

        return new String(data);
    }

    // 生成文件
    public static File makeFilePath(String filePath, String fileName) {
        File file = null;
        makeRootDirectory(filePath);
        try {
            file = new File(filePath + fileName);
            if (!file.exists()) {
                file.createNewFile();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return file;
    }

    // 生成文件夹
    public static void makeRootDirectory(String filePath) {
        File file = null;
        try {
            file = new File(filePath);
            if (!file.exists()) {
                file.mkdir();
            }
        } catch (Exception e) {
            Log.i("error:", e + "");
        }
    }

    //吐司
    public static void Toast(Context context, String str) {
        Toast.makeText(context, str, Toast.LENGTH_SHORT).show();
    }


    //保存图片
    public static void SaveImage(String savePath, boolean isDir, String name, Bitmap bitmap, Context context) {


        File files = null;
        File file = null;

        if (TextUtils.isEmpty(savePath)) {
            File dcimFile = new File(Environment.getExternalStorageDirectory(), "Alva");
            files = new File(dcimFile, "zx");
            //　保存的路径
            //   file = new File(files, System.currentTimeMillis() + ".jpg");
            file = new File(files, name);
        } else {
            if (isDir) {
                files = new File(savePath);
                //　保存的路径
                //file = new File(files, System.currentTimeMillis() + ".jpg");
                file = new File(files, name);
            } else {
                file = new File(savePath);
                files = file.getParentFile();
            }
        }
        files.mkdirs();

        FileOutputStream outputStream = null;
        try {
            outputStream = new FileOutputStream(file);
            bitmap.compress(Bitmap.CompressFormat.JPEG, 100, outputStream);
            ImageUtils.addImage(context.getContentResolver(), file.getAbsolutePath());

        } catch (Exception e) {
            e.printStackTrace();

        } finally {
            if (outputStream != null) {
                try {
                    outputStream.close();

                } catch (IOException e) {
                }
            }
        }

    }


}