webview中的img标签加载Android本地的图片

第一种：本地Html加载本地图片（不存在跨域问题）

注意问题：一定是file:///开头，注意是三个斜杠

例如： String path= "file://" +Environment.getExternalStorageDirectory()+ File.separator+ "meimei.jpg" ;

代码如下：

package com.example.a5.myapplication;  
  
import android.os.Environment;  
import android.support.v7.app.AlertDialog;  
import android.support.v7.app.AppCompatActivity;  
import android.os.Bundle;  
import android.webkit.WebChromeClient;  
import android.webkit.WebSettings;  
import android.webkit.WebView;  
  
import java.io.File;  
  
public class MainActivity extends AppCompatActivity {  
    private WebView webView;  
    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_main);  
        webView= (WebView) findViewById(R.id.webView);  
        WebSettings webSettings=webView.getSettings();  
        //允许webview对文件的操作  
        webSettings.setAllowUniversalAccessFromFileURLs(true);  
        webSettings.setAllowFileAccess(true);  
        webSettings.setAllowFileAccessFromFileURLs(true);  
        //用于js调用Android  
        webSettings.setJavaScriptEnabled(true);  
        //设置编码方式  
        webSettings.setDefaultTextEncodingName("utf-8");  
        webView.setWebChromeClient(new chromClient());  
        //访问Android assets文件夹内的  
        String url="file:///android_asset/test.html";  
        //访问网页Html  
//        String url="http://192.168.1.121:8080/jsandroid/index.html"；  
        runWebView(url);  
  
    }  
    private class chromClient extends WebChromeClient{  
        @Override  
        public void onProgressChanged(WebView view, int newProgress) {  
            if(newProgress==100){  
                //页面加载完成执行的操作  
                String path= "file://"+Environment.getExternalStorageDirectory()+ File.separator+"123.jpg";  
                String action="javascript:aa('"+path+"')";  
                new AlertDialog.Builder(MainActivity.this)  
                        .setMessage(action)  
                        .show();  
                runWebView(action);  
            }  
            super.onProgressChanged(view, newProgress);  
        }  
    }  
  
    private void runWebView(final String url){  
        runOnUiThread(new Runnable() {  
            @Override  
            public void run() {  
                webView.loadUrl(url);  
            }  
        });  
    }  
}

第二种：非本地Html加载本地图片（存在跨域问题）

解决方式：

步骤一：对 img标签增加

方法一：（未成功）

crossorigin="anonymous"属性

< img src="../img/addImg.png" alt="" style="width:100%;height:100%" crossorigin="anonymous">

步骤二: 在

webView.loadUrl(url)之前增加：

 try {
            if (Build.VERSION.SDK_INT >= 16) {
                Class<?> clazz = hybridWebView.getSettings().getClass();
                Method method = clazz.getMethod(
                        "setAllowUniversalAccessFromFileURLs", boolean.class);
                if (method != null) {
                    method.invoke(hybridWebView.getSettings(), true);
                }
            }
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }

最后：webView.loadUrl(url)
方法二：将图片转换为Base64 （成功）

转为Base64 代码为：

package com.channelsoft.livev114.utils;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Base64;

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

/**
 * <pre>
 *     author: zhaojz
 *     crateTime  :2018/2/24
 *     email :[email protected]
 *     desc  : 描述
 *     mender:暂无其他修改者
 *     modificationTime:修改时间
 *     modificationDesc:暂无修改描述
 * </pre>
 */

public class ReadImgToBinary2 {

    /**
     *
     * @param imgPath
     * @param bitmap
     * @param imgFormat 图片格式
     * @return
     */
    public static String imgToBase64(String imgPath, Bitmap bitmap, String imgFormat) {
        if (imgPath !=null && imgPath.length() > 0) {
            bitmap = readBitmap(imgPath);
        }
        if(bitmap == null){
            //bitmap not found!!
        }
        ByteArrayOutputStream out = null;
        try {
            out = new ByteArrayOutputStream();
            bitmap.compress(Bitmap.CompressFormat.JPEG, 100, out);

            out.flush();
            out.close();

            byte[] imgBytes = out.toByteArray();
            return Base64.encodeToString(imgBytes, Base64.DEFAULT);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            return null;
        } finally {
            try {
                out.flush();
                out.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

    private static Bitmap readBitmap(String imgPath) {
        try {
            return BitmapFactory.decodeFile(imgPath);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            return null;
        }

    }

    /**
     *
     * @param base64Data
     * @param imgName
     * @param imgFormat 图片格式
     */
    public static void base64ToBitmap(String base64Data,String imgName,String imgFormat) {
        byte[] bytes = Base64.decode(base64Data, Base64.DEFAULT);
        Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);

        File myCaptureFile = new File("/sdcard/", imgName);
        FileOutputStream fos = null;
        try {
            fos = new FileOutputStream(myCaptureFile);
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        boolean isTu = bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos);
        if (isTu) {
            // fos.notifyAll();
            try {
                fos.flush();
                fos.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        } else {
            try {
                fos.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
}

webView调用代码：

  String urlBase64 =  ReadImgToBinary2.imgToBase64(images.get(0).path,null,"");
                    String urlBase64PosterImg = "data:image/png;base64,"+urlBase64;
                    hybridWebView.loadUrl("javascript:posterImg('" + urlBase64PosterImg+ "')");

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webview中的img标签加载Android本地的图片

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