webView 使用指南及使用心得总结

MainActivity

package test.ban.com.webview;
import android.annotation.TargetApi;
import android.content.Intent;
import android.graphics.Bitmap;
import android.net.http.SslError;
import android.os.Build;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.KeyEvent;
import android.view.View;
import android.webkit.JavascriptInterface;
import android.webkit.JsResult;
import android.webkit.SslErrorHandler;
import android.webkit.ValueCallback;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;
import java.lang.reflect.Field;
public class MainActivity extends AppCompatActivity {
private WebView mWebView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.act_main);
initView();
}
private void initView() {
mWebView = (WebView) findViewById(R.id.wb);
mWebView.getSettings().setJavaScriptEnabled(true);//支持javascript
mWebView.requestFocus();//触摸焦点起作用
mWebView.setScrollBarStyle(WebView.SCROLLBARS_OUTSIDE_OVERLAY);//取消滚动条
mWebView.getSettings().setJavaScriptCanOpenWindowsAutomatically(true);//设置允许js弹出alert对话框
//load本地
mWebView.loadUrl("file:///android_asset/hellotest.html");
//load在线
//mWebView.loadUrl("http://www.google.com");
//js访问android，定义接口
mWebView.addJavascriptInterface(new JsInteration(), "control");
/**
* 调用方法例子:window.control.toastMessage(message)
* js调用Java
调用格式为window.jsInterfaceName.methodName(parameterValues)
此例中我们使用的是control作为注入接口名称。
*/
//设置了Alert才会弹出，重新onJsAlert（）方法return true可以自定义处理信息
mWebView.setWebChromeClient(new WebChromeClient() {
@Override
public boolean onJsAlert(WebView view, String url, String message, JsResult result) {
//return super.onJsAlert(view, url, message, result);
Toast.makeText(MainActivity.this, message, Toast.LENGTH_LONG).show();
return true;
}
});
mWebView.setWebViewClient(new WebViewClient() {
@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
//在当前的webview中跳转到新的url
view.loadUrl(url);
//启动手机浏览器来打开新的url
//
Intent i = new Intent(Intent.ACTION_VIEW);
//
i.setData(Uri.parse(url));
//
startActivity(i);
return true;
}
//载入页面开始的事件
@Override
public void onPageStarted(WebView view, String url, Bitmap favicon) {
super.onPageStarted(view, url, favicon);
}
// 载入页面完成的事件
@Override
public void onPageFinished(WebView view, String url) {
super.onPageFinished(view, url);
}
//webView默认是不处理https请求的，页面显示空白，需要进行如下设置：
@Override
public void onReceivedSslError(WebView view, SslErrorHandler handler, SslError error) {
handler.proceed();//如果只是简单的接受所有证书的话，就直接调process()方法就行了
// handler.cancel();
// handler.handleMessage(null); } });
}
});
}
/**
* android调用js无参无返回值函数
*
* @param view
*/
public void Android2JsNoParmNoResult(View view) {
final String call = "javascript:sayHello()";
mWebView.post(new Runnable() {
@Override
public void run() {
mWebView.loadUrl(call);
}
});
}
/**
* android调用js有参无返回值函数
*
* @param view
*/
public void Android2JsHaveParmNoResult(View view) {
final String call = "javascript:alertMessage("" + "我是android传过来的内容,hey man" + "")";
mWebView.post(new Runnable() {
@Override
public void run() {
mWebView.loadUrl(call);
}
});
}
/**
* android调用js有参有返回值函数（4.4之前）
*
* @param view
*/
public void Android2JsHaveParmHaveResult(View view) {
final String call = "javascript:sumToJava(1,2)";
mWebView.post(new Runnable() {
@Override
public void run() {
mWebView.loadUrl(call);
}
});
}
/**
* android调用js有参有返回值函数（4.4之后）
* evaluateJavascript方法必须在UI线程（主线程）调用，因此onReceiveValue也执行在主线程
*
* @param view
*/
@TargetApi(Build.VERSION_CODES.KITKAT)
public void Android2JsHaveParmHaveResult2(View view) {
mWebView.evaluateJavascript("sumToJava2(3,4)", new ValueCallback<String>() {
@Override
public void onReceiveValue(String Str) {
Toast.makeText(getApplicationContext(), "我是android调用js方法(4.4后)，入参是3和4，js返回结果是" +
Str, Toast.LENGTH_LONG).show();
}
});
}
/**
* 获取网页图片并放大显示
*
* @param view
*/
public void clickPhoto(View view) {
startActivity(new Intent(this, WithPhotoWebActivity.class));
}
/**
* js调用android的方法
*/
class JsInteration {
@JavascriptInterface
public void toastMessage(String message) {
Toast.makeText(getApplicationContext(), message, Toast.LENGTH_LONG).show();
}
@JavascriptInterface
public void onSumResult(int result) {
Toast.makeText(getApplicationContext(), "我是android调用js方法(4.4前)，入参是1和2，js返回结果是" +
result, Toast.LENGTH_LONG).show();
}
}
/**
* 网页回退
*
* @param keyCode
* @param event
* @return
*/
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK && mWebView.canGoBack()) {
mWebView.goBack();// 返回前一个页面
return true;
}
return super.onKeyDown(keyCode, event);
}
@Override
protected void onDestroy() {
if (mWebView != null) {
mWebView.setVisibility(View.GONE);
mWebView.removeAllViews();
mWebView.destroy();
releaseAllWebViewCallback();
}
super.onDestroy();
}
/**
* 防止内存泄露
*/
public void releaseAllWebViewCallback() {
if (Build.VERSION.SDK_INT < 16) {
try {
Field field = WebView.class.getDeclaredField("mWebViewCore");
field = field.getType().getDeclaredField("mBrowserFrame");
field = field.getType().getDeclaredField("sConfigCallback");
field.setAccessible(true);
field.set(null, null);
} catch (NoSuchFieldException e) {
if (BuildConfig.DEBUG) {
e.printStackTrace();
}
} catch (IllegalAccessException e) {
if (BuildConfig.DEBUG) {
e.printStackTrace();
}
}
} else {
try {
Field sConfigCallback = Class.forName("android.webkit.BrowserFrame")
.getDeclaredField("sConfigCallback");
if (sConfigCallback != null) {
sConfigCallback.setAccessible(true);
sConfigCallback.set(null, null);
}
} catch (NoSuchFieldException e) {
if (BuildConfig.DEBUG) {
e.printStackTrace();
}
} catch (ClassNotFoundException e) {
if (BuildConfig.DEBUG) {
e.printStackTrace();
}
} catch (IllegalAccessException e) {
if (BuildConfig.DEBUG) {
e.printStackTrace();
}
}
}
}
}

WithPhotoWebActivity

package test.ban.com.webview;
import android.graphics.Bitmap;
import android.os.Build;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.KeyEvent;
import android.view.View;
import android.webkit.JavascriptInterface;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.ProgressBar;
import android.widget.Toast;
/**
* des:带图片的webview网站
*/
public class WithPhotoWebActivity extends AppCompatActivity {
private WebView mWebView;
private ProgressBar pg;
private String mShareUrl;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.act_with_photo_webview);
initView();
}
private void initView() {
pg = (ProgressBar) findViewById(R.id.pg);
pg.setVisibility(View.VISIBLE);
mWebView = (WebView) findViewById(R.id.wb);
if (Build.VERSION.SDK_INT >= 19) {
mWebView.getSettings().setCacheMode(WebSettings.LOAD_CACHE_ELSE_NETWORK);
}
// 启用javascript
mWebView.getSettings().setJavaScriptEnabled(true);
// 找了个带图片的网站
mWebView.loadUrl("http://sc.chinaz.com/tupian/beijingtupian.html");
// 添加js交互接口类，并起别名 imagelistner
mWebView.addJavascriptInterface(this, "imagelistner");
mWebView.setWebViewClient(new MyWebViewClient());
//长按获取图片链接
mWebView.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View view) {
/**
* ----如何获取所点击或者所选内容----
长按webView上所选内容，可触发OnLongClickListener，
以此可以来判断所选内容的类型，来做不同的处理。
这类需要了解一下getHitTestResult()函数的使用。
int IMAGE_TYPE HitTestResult for hitting an HTML::imgtag
int SRC_IMAGE_ANCHOR_TYPE HitTestResult for hitting a HTML::a tagwith src=http +
HTML::img
*/
WebView.HitTestResult result = mWebView.getHitTestResult();
if (result != null) {
int type = result.getType();
if (type == WebView.HitTestResult.IMAGE_TYPE || type == WebView.HitTestResult
.SRC_IMAGE_ANCHOR_TYPE) {
String imgurl = result.getExtra();
Toast.makeText(WithPhotoWebActivity.this, imgurl, Toast.LENGTH_SHORT)
.show();
}
}
return true;
}
});
}
// js通信接口
@JavascriptInterface
public void openImage(String img) {
System.out.println(img);
ShowWebImageActivity.startAction(this, img);
System.out.println(img);
}
// 注入js函数监听
private void addImageClickListner() {
// 这段js函数的功能就是，遍历所有的img几点，并添加onclick函数，在还是执行的时候调用本地接口传递url过去
mWebView.loadUrl("javascript:(function(){" +
"var objs = document.getElementsByTagName("img"); " +
"for(var i=0;i<objs.length;i++)
" +
"{"
+ "
objs[i].οnclick=function()
" +
"
{
"
+ "
window.imagelistner.openImage(this.src);
" +
"
}
" +
"}" +
"})()");
/**
this.src
是img的属性，通过改变img的属性src就可以更换验证码的图片
*/
}
// 监听
private class MyWebViewClient extends WebViewClient {
@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
//在当前的webview中跳转到新的url
view.loadUrl(url);
return true;
}
@Override
public void onPageFinished(WebView view, String url) {
view.getSettings().setJavaScriptEnabled(true);
pg.setVisibility(View.GONE);
super.onPageFinished(view, url);
// html加载完成之后，添加监听图片的点击js函数
addImageClickListner();
}
@Override
public void onPageStarted(WebView view, String url, Bitmap favicon) {
view.getSettings().setJavaScriptEnabled(true);
super.onPageStarted(view, url, favicon);
}
@Override
public void onReceivedError(WebView view, int errorCode, String description, String
failingUrl) {
super.onReceivedError(view, errorCode, description, failingUrl);
}
}
/**
* 网页回退
*
* @param keyCode
* @param event
* @return
*/
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK && mWebView.canGoBack()) {
mWebView.goBack();// 返回前一个页面
return true;
}
return super.onKeyDown(keyCode, event);
}
@Override
protected void onDestroy() {
if (mWebView != null) {
mWebView.setVisibility(View.GONE);
mWebView.removeAllViews();
mWebView.destroy();
}
super.onDestroy();
}
}

ShowWebImageActivity

package test.ban.com.webview;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.ImageView;
import android.widget.TextView;
import com.bumptech.glide.Glide;
import com.bumptech.glide.load.engine.DiskCacheStrategy;
/**
* des:显示web大图
*/
public class ShowWebImageActivity extends AppCompatActivity {
private TextView imageTextView = null;
private ImageView img;
private String imagePath = null;
public static void startAction(Context context, String image) {
Intent intent = new Intent(context, ShowWebImageActivity.class);
intent.putExtra("image", image);
context.startActivity(intent);
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.act_show_big_photo);
this.imagePath = getIntent().getStringExtra("image");
this.imageTextView = (TextView) findViewById(R.id.tv_url);
img = (ImageView) findViewById(R.id.img);
imageTextView.setText(this.imagePath);
//通过框架Glide把图片显示在imageView上
Glide.with(this).load(imagePath)
.diskCacheStrategy(DiskCacheStrategy.ALL)
.thumbnail(0.1f).into(img);
}
}

最后

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