木子屋 - Android编程

WebView控件打不开网页提示ERR_UNKNOWN_URL_SCHEME解决方法

service@mzwu.com(dnawo) — Thu,20 Oct 2016 13:14:31 +0800

网址前边是taobao://而不是http://，分析是淘宝电脑版页面判断出当前是手机用户，尝试调用淘宝客户端出错，将WebView.loadUrl方法中电脑版网页地址改成手机版网页地址即可：

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webView.loadUrl("https://item.taobao.com/item.htm?id=38946217400");

修改为：

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webView.loadUrl("http://h5.m.taobao.com/awp/core/detail.htm?id=38946217400");

Google Play发布Android应用示例

service@mzwu.com(dnawo) — Sun,16 Oct 2016 15:34:57 +0800

在Google Play发布Android应用流程还是比较简单的，先注册一个 Google Play 发布者帐户(需支付25美元)，然后上传应用并填写相关应用信息就可以发布了：

整个过程比较麻烦的是怎么支付那25美元注册费，我试了国内几家银行信用卡都不能支付，后来知道有虚拟信用卡这种东东，在万事达卡全球付网站上申请了一张，并最终支付成功完成注册：

PS：万事达卡全球付申请成功后会分配一张虚拟卡，有卡号、有效期、安全码等基本信息，需先充值后消费，可提现，仅能用于网上支付。

相关链接

[1].开始发布应用：https://developer.android.com/distribute/googleplay/start.html
[2].Google Play开发者平台：https://play.google.com/apps/publish/?hl=zh-CN
[3].万事达卡全球付：https://www.globalcash.hk/
[4].易简学汉语拼音点读机：https://play.google.com/store/apps/details?id=com.neargou.pinyin

Android设置Theme.NoTitleBar去除标题栏总出错解决方法

service@mzwu.com(dnawo) — Sat,15 Oct 2016 08:23:55 +0800

在AndroidManifest.xml配置去除应用标题栏，手机安装后一打开就出错：

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    android:name=".MainActivity"
    android:theme="@android:style/Theme.NoTitleBar">

接着尝试在代码中去除标题栏，也是一打开就出错：

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getWindow().requestFeature(Window.FEATURE_NO_TITLE);

最后发现原因是我的Activity继承自AppCompatActivity，改成Activity再用上边任一种方法都可去除应用标题栏：

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public class MainActivity extends Activity

其实在创建Activity时可以选择的，只是没留意：

资料参考

[1].android应用中去掉标题栏的方法：http://blog.csdn.net/liuzhidong123/article/details/7818531
[2].解决安卓添加Theme.NoTitleBar报错问题：http://blog.csdn.net/gs12software/article/details/44570399
[3].解决无法在theme中设置NoTitleBar属性的问题：http://blog.csdn.net/helene1996/article/details/52643557

Android使用MediaPlayer播放mp3音乐示例

service@mzwu.com(dnawo) — Fri,14 Oct 2016 21:15:33 +0800

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package com.mzwu.www;

import android.content.res.AssetFileDescriptor;
import android.media.MediaPlayer;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.view.View.OnClickListener;
import android.widget.EditText;
import android.widget.Toast;
import java.io.IOException;

public class MainActivity extends AppCompatActivity {
    //播放器
    private MediaPlayer mp = new MediaPlayer();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //开始播放
        Button btnPlay = (Button)findViewById(R.id.button);
        btnPlay.setOnClickListener(new OnClickListener(){
            public void onClick(View v) {
                String soundfile = ((EditText)findViewById(R.id.editText)).getText().toString();
                try {
                    mp.reset();
                    if(soundfile.startsWith("http:")){
                        mp.setDataSource(soundfile);
                    }else{
                        AssetFileDescriptor fileDescriptor = MainActivity.this.getAssets().openFd(soundfile);
                        mp.setDataSource(fileDescriptor.getFileDescriptor(),
                                fileDescriptor.getStartOffset(),
                                fileDescriptor.getLength());
                        fileDescriptor.close();
                    }
                    mp.prepare();
                    mp.start();
                } catch (IllegalArgumentException e) {
                    e.printStackTrace();
                } catch (IllegalStateException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        });

        //播放结束
        mp.setOnCompletionListener(new MediaPlayer.OnCompletionListener(){
            public void onCompletion(MediaPlayer mp) {
                Toast.makeText(MainActivity.this, "播放结束！", Toast.LENGTH_SHORT).show();
            }
        });
    }

    //释放播放器占用的资源
    @Override
    protected void onDestroy() {
        if(mp != null)
        {
            mp.release();
        }
        super.onDestroy();
    }
}

参考资料

[1].深入Android MediaPlayer的使用方法详解：http://www.jb51.net/article/38722.htm
[2].Android MediaPlayer基本使用方式：http://blog.csdn.net/ddna/article/details/5176233
[3].MediaPlayer实现列表选歌：http://www.cnblogs.com/snake-hand/archive/2013/02/22/2922923.html
[4].创建OnClickListener方法报错的解决办法：http://blog.csdn.net/wpyily/article/details/46503709

Playing Audio on Android from an HTML5 File[转]

service@mzwu.com(dnawo) — Fri,14 Oct 2016 10:09:34 +0800

Introduction

Earlier today, I came across a problem. I have been working on an App in Android that displays HTML5 files from the assets folder inside a WebView. One of the big problems with playing Audio in an HTML5 page is that a lot of browsers do not support the tag; this includes several versions of the WebView control in different versions of Android. The bottom line is that you can't expect standardized results across different versions of Android when using the HTML5 tag. So we're going to use a workaround that uses the native Android method of playing audio.

Here is a synopsis of the paragraphs below that describe how to implement the code.

·Configuring your WebView control
·Creating an Audio Interface for the HTML5 web page
·Attaching the Audio Interface to the WebView control
·Invoking an Audio Interface function from the HTML5 page using Javascript

Implementing the Code

Configuring your WebView control

Create a WebView control inside your layout. This is the XML code for the layout I used:

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http://schemas.android.com/apk/res/android"
    android:id="@+id/webview"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" />

This is the Java that I used to initially configure the WebView:

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//Configures the WebView during the onCreate method
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    WebView myWebView = (WebView) findViewById(R.id.webview);

    //Set it to a webChromeClient
    myWebView.setWebChromeClient(new WebChromeClient());

    //the default for WebView is that Javascript isn't enabled in WebView
    myWebView.getSettings().setJavascriptEnabled(true);

    //the index.html file is placed in the assets folder
    myWebView.loadUrl("file:///android_asset/index.html");
}

Creating an Audio Interface for the HTML5 web page

Next, we're going to create an AudioInterface Java class to play audio MP3s from the assets folder.

Create a new Java Class and call it "AudioInterface.Java"

Here is the Java code for the class:

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import java.io.IOException;
import android.content.Context;
import android.content.res.AssetFileDescriptor;
import android.media.MediaPlayer;
import android.webkit.JavascriptInterface;

public class AudioInterface {
    Context mContext;

    AudioInterface(Context c) {
        mContext = c;
    }

    //Play an audio file from the webpage
    @JavascriptInterface
    public void playAudio(String aud) { //String aud - file name passed
                                        //from the Javascript function
        final MediaPlayer mp;

              try {
                  AssetFileDescriptor fileDescriptor =
                          mContext.getAssets().openFd(aud);
                                    mp = new MediaPlayer();
                                    mp.setDataSource(fileDescriptor.getFileDescriptor(),
                                    fileDescriptor.getStartOffset(),
                                    fileDescriptor.getLength());
                                    fileDescriptor.close();
                                    mp.prepare();
                                    mp.start();
              } catch (IllegalArgumentException e) {
                              // TODO Auto-generated catch block
                              e.printStackTrace();
                    } catch (IllegalStateException e) {
                              // TODO Auto-generated catch block
                              e.printStackTrace();
                    } catch (IOException e) {
                              // TODO Auto-generated catch block
                              e.printStackTrace();
              }
    }
}

The above code creates a public method that accepts a string argument which is used as the URL for the mp3 file location. So I store my mp3 files in a sub folder in the assets folder called audio. So the playAudio method needs an argument similar to this: "audio/example.mp3". If it was stored directly in the assets folder it would look like this: "example.mp3".

Attaching the Audio Interface to the WebView control

Now, we need to attach the AudioInterface class to the WebView control in the onCreate method in order to make it available for the Javascript code. So add the following code to the onCreate method we edited earlier in the layout's Java file:

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myWebView.addJavascriptInterface(new AudioInterface(this), "AndAud");

Invoking an Audio Interface function from the HTML5 page using Javascript

Now we can call the playAudio function from Javascript inside the HTML5 file by using this method:

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And that's it, it's kind of an annoying work around but at least you know it will work rather than waiting on the kinks to be worked out.

dnawo补充：

若想让playAudio方法也能播放网络音频，只需稍做修改即可：

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@JavascriptInterface
public void playAudio(String aud) {
    final MediaPlayer mp;

    try {
        mp = new MediaPlayer();
        if(aud.startsWith("http://")){
            mp.setDataSource(aud);
        }else{
            AssetFileDescriptor fileDescriptor = mContext.getAssets().openFd(aud);
            mp.setDataSource(fileDescriptor.getFileDescriptor(),
                    fileDescriptor.getStartOffset(),
                    fileDescriptor.getLength());
            fileDescriptor.close();
        }
        mp.prepare();
        mp.start();
    } catch (IllegalArgumentException e) {
        e.printStackTrace();
    } catch (IllegalStateException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

资源链接

[1].原文链接：http://www.codeproject.com/Tips/677841/Playing-Audio-on-Android-from-an-HTML-File
[2].Playing local audio file in Android webview app：http://stackoverflow.com/questions/9201893/playing-local-audio-file-in-android-webview-app
[3].android webview加载html5 audio标签路径问题：http://zhidao.baidu.com/question/589462287

Androrid控件WebView使用示例

service@mzwu.com(dnawo) — Thu,13 Oct 2016 22:52:08 +0800

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protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    //setContentView(R.layout.activity_main);

    //WebView控件
    WebView webView = new WebView(this);
    webView.getSettings().setJavascriptEnabled(true);
    webView.loadUrl("http://www.mzwu.com/");
    //webView.loadUrl("file:///android_asset/Index.html");
    setContentView(webView);
    //禁止WebView调用系统浏览器或第三方浏览器
    webView.setWebViewClient(new WebViewClient() {
        public boolean shouldOverrideUrlLoading(WebView view, String url)
        {
            view.loadUrl(url);
            return true;
        }
    });
}

记得在AndroidManifest.xml设置访问网络权限：

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http://schemas.android.com/apk/res/android"
    package="com.mzwu.www">

            android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">

手机移动端不能触发jQuery双击事件dblclick解决方法

service@mzwu.com(dnawo) — Thu,13 Oct 2016 20:18:05 +0800

今天意外发现移动手机端不能触发jQuery的dblclick事件，做了个简单的页面重现问题：

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如上图所示，手机端只触发了两次click事件，没有触发dblclick事件。既然click事件都能正常触发，那么我们应该可以通过判断两次单击间隔时间来模拟dblclick双击事件，修改脚本如下：

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OK，问题解决！

Android连续按两次返回键退出应用示例

service@mzwu.com(dnawo) — Thu,13 Oct 2016 13:55:38 +0800

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import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.KeyEvent;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    //记录第一次按返回键的时间
    private long mExitTime = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    //5秒内按两次返回键退出应用
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            if ((System.currentTimeMillis() - mExitTime) > 5000) {
                Toast.makeText(this, "再按一次退出应用", Toast.LENGTH_SHORT).show();
                mExitTime = System.currentTimeMillis();
            } else {
                finish();
            }
            return true;
        }
        return super.onKeyDown(keyCode, event);
    }
}

启动Android Studio一直停在fetching Android sdk compoment解决方法

service@mzwu.com(dnawo) — Fri,16 Jan 2015 15:46:38 +0800

进入Android Studio安装文件夹，打开bin/idea.properties文件，在末尾添加下边内容即可解决：

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disable.android.first.run=true

怎么查看安卓手机WiFi密码

service@mzwu.com(dnawo) — Mon,16 Jun 2014 01:41:33 +0800

安卓手机WiFi密码以明文形式保存在/data/misc/wifi/wpa_supplicant.conf文件中，安装Root Explorer、ES文件浏览器等应用赋于root权限打开该文件即可查看WiFi密码：