图片工具类
package com.example.save_pic_delete;
import android.content.ContentResolver;
import android.content.ContentUris;
import android.content.Context;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Environment;
import android.provider.MediaStore;
import android.text.TextUtils;
import android.util.Base64;
import android.widget.ImageView;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
/**
* 图片相关的工具类
*/
public class ImageUtils {/**
* base64字符串转化成图片
*/
public static String GenerateImage(Context context, String imgStr) {//对字节数组字符串进行Base64解码并生成图片
if (imgStr == null) { //图像数据为空
UtilsTools.MsgBox(context, "图片不能为空");
return "";
}try {
//Base64解码
byte[] b = Base64Utils.decode(imgStr);
for (int i = 0;
i < b.length;
++i) {
if (b[i] < 0) {//调整异常数据
b[i] += 256;
}
}
// 新生成的jpg图片
// 新图片的文件夹, 如果没有, 就创建
String dirPath = Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES).getAbsolutePath() + "/zdgj/";
File fileDir = new File(dirPath);
if (!fileDir.exists()) {
fileDir.mkdirs();
}
// 文件夹现在存在了, 可以在此文件夹下创建图片了
String imgFilePath = dirPath + System.currentTimeMillis() + ".jpg";
File file = new File(imgFilePath);
if (!file.exists()) {
file.createNewFile();
}
OutputStream out = new FileOutputStream(imgFilePath);
out.write(b);
out.flush();
out.close();
SharedPrefUtil.putString(context, SharedPreConstant.FacePicPathKey, imgFilePath);
UtilsTools.MsgBox(context, "图片已保存到本地");
return imgFilePath;
} catch (Exception e) {
UtilsTools.MsgBox(context, e.getMessage());
return "";
}
}/**
* 将图片转换成Base64编码的字符串
*
* @param path 图片本地路径
* @return base64编码的字符串
*/
public static String imageToBase64(String path) {
if (TextUtils.isEmpty(path)) {
return null;
}
InputStream is = null;
byte[] data;
String result = null;
try {
is = new FileInputStream(path);
//创建一个字符流大小的数组。
data = https://www.it610.com/article/new byte[is.available()];
//写入数组
is.read(data);
//用默认的编码格式进行编码
result = Base64.encodeToString(data, Base64.DEFAULT);
} catch (IOException e) {
e.printStackTrace();
} finally {
if (null != is) {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return result;
}/**
* 在ImageView里展示指定路径的图片
*
* @param path本地路径
* @param imageView ImageView
*/
public static void ShowPic2View(Context context, String path, ImageView imageView) {
File localFile;
FileInputStream localStream;
Bitmap bitmap;
localFile = new File(path);
if (!localFile.exists()) {
UtilsTools.MsgBox(context, path +" is null.");
} else {
try {
localStream = new FileInputStream(localFile);
bitmap = BitmapFactory.decodeStream(localStream);
imageView.setImageBitmap(bitmap);
//if (localStream != null) {
localStream.close();
//}
} catch (Exception e) {
e.printStackTrace();
UtilsTools.MsgBox(context, e.getMessage());
}
}
}/**
* 删除手机里指定路径的图片
*
* @param context Context
* @param imgPath 本地路径
*/
public static void DeletePicFromMobile(Context context, String imgPath) {
try {
ContentResolver resolver = context.getContentResolver();
Cursor cursor = MediaStore.Images.Media.query(resolver, MediaStore.Images.Media.EXTERNAL_CONTENT_URI, new String[]{MediaStore.Images.Media._ID}, MediaStore.Images.Media.DATA + "=?", new String[]{imgPath}, null);
boolean result;
if (cursor.moveToFirst()) {
long id = cursor.getLong(0);
Uri contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
Uri uri = ContentUris.withAppendedId(contentUri, id);
int count = context.getContentResolver().delete(uri, null, null);
result = count == 1;
} else {
File file = new File(imgPath);
result = file.delete();
}if (result) {
UtilsTools.MsgBox(context, "删除成功");
}
} catch (Exception e) {
UtilsTools.MsgBox(context, e.getMessage());
}
}
}验证图片工具类的demo :
Activity :
package com.example.save_pic_delete;
import android.content.Context;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import java.io.File;
public class MainActivity extends AppCompatActivity {private ImageView iv_main;
private TextView tv_delete;
private TextView tv_check;
private Context mContext;
private String filePath1;
private String filePath;
private String base64Str;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
mContext = this;
// 原图路径
filePath1 = "/storage/emulated/0/tencent/MicroMsg/WeiXin/mmexport1542093665881.jpg";
// 展示原图
ImageUtils.ShowPic2View(mContext, filePath1, iv_main);
// 原图base64
base64Str = ImageUtils.imageToBase64(filePath1);
// base64的原图另存为到本项目路径
filePath = ImageUtils.GenerateImage(mContext, base64Str);
}private void initView() {
iv_main = findViewById(R.id.iv_main);
tv_delete = findViewById(R.id.tv_delete);
tv_check = findViewById(R.id.tv_check);
// 删除
tv_delete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// 删除本项目下保存的那个指定路径的图片
ImageUtils.DeletePicFromMobile(mContext, filePath);
}
});
// 检测
tv_check.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
File file = new File(filePath);
if (!file.exists()) {
UtilsTools.MsgBox_Long(mContext, "这个图片现在不存在");
} else {
UtilsTools.MsgBox_Long(mContext, "这个图片存在");
}
}
});
}
}Activity的布局 : (只有一个显示base64转出图片的ImageView和一个删除按钮和一个检测本张图片还在不在本机的检测按钮)
其他没有注明的小类在其他文章中有贴过完整代码 :
- SharedPrefUtil 为自己写的一个 SharedPreferences存储工具类 https://blog.csdn.net/qq_28261207/article/details/79853165
- Base64加密解密工具类 : https://blog.csdn.net/qq_28261207/article/details/84249623
