软硬件环境
- Macbook pro MGX 72
- 红米Note增强版
- Android studio 1.0.2
概述
Android
的javascript
扩展,即Android
提供了javascript
网页脚本调用java
类方法的机制。方法其实很简单,只要调用addJavascriptInterface
方法即可映射一个java
对象到javascript
对象。
示例
Android
代码
package com.macernow.djstava;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.webkit.JavascriptInterface;
import android.webkit.WebView;
public class MainActivity extends ActionBarActivity {
private static final String TAG = "MainActivity";
private WebView webView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
webView = (WebView)findViewById(R.id.webView);
webView.getSettings().setJavaScriptEnabled(true);
webView.addJavascriptInterface(this,"djstava");
webView.loadUrl("http://192.168.31.109/demo.html");
}
@JavascriptInterface
public void jsextent() {
Log.e(TAG,"========== js extension success.");
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
WebView
一定要使能javascript
。在Android 4.2
之后,抛出给javascript
的java
方法必须加上@JavascriptInterface
。
布局文件
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">
<WebView
android:id="@+id/webView"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
</WebView>
</RelativeLayout>
测试页面
在javascript
脚本中调用java
方法
window.djstava.jsextent()