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 :zhaojz@channelsoft.com
*     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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