Android實戰--電話撥號器

今天跟著黑馬視頻建立一個android app--電話撥號器

首先新建一個android項目

activity_main_xml中的代碼如下:

<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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <!-- 文本框 -->
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="請輸入號碼" />
    <EditText 
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        />
</RelativeLayout>

運行一下：

可以看到佈局出現問題，文字出現重疊，簡單的解決方法如下：

<LinearLayout 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"
    tools:context=".MainActivity" 
    android:orientation="vertical"
    >
    <!-- 文本框 -->
    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="請輸入號碼" />

    <EditText
        android:id="@+id/et_number"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
       />

    <Button 
        android:id="@+id/bt_call"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="撥打"
        />
</LinearLayout>

界面如下所示：

MainActivity中添加下麵的代碼：

package com.wuyudong.dial;

import android.net.Uri;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        // 通過資源id獲取到佈局文件中的 對應的組件
        Button bt = (Button) findViewById(R.id.bt_call);

        // 給按鈕設置監聽
        bt.setOnClickListener(new MyListener());
    }

    class MyListener implements OnClickListener {

        // 當按鈕被點擊的時候，此方法會被調用
        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            System.out.println("按鈕被點擊了！");
            // 通過資源id獲取到輸入框
            EditText et = (EditText) findViewById(R.id.et_number);
            // 獲取輸入框的內容
            String number = et.getText().toString().trim();
            // 告訴系統我們的動作是打電話
            Intent intent = new Intent();
            // 設置動作
            intent.setAction(Intent.ACTION_CALL);
            // 設置打給誰
            intent.setData(Uri.parse("tel:" + number));
            //啟動打電話應用,把意圖告訴系統
            startActivity(intent);
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

}

撥打電話後，出現如下異常：

05-26 19:43:02.155: D/dalvikvm(2042): Not late-enabling CheckJNI (already on)
05-26 19:43:02.775: D/gralloc_goldfish(2042): Emulator without GPU emulation detected.
05-26 19:43:22.015: I/System.out(2042): 按鈕被點擊了！
05-26 19:43:22.015: D/AndroidRuntime(2042): Shutting down VM
05-26 19:43:22.015: W/dalvikvm(2042): threadid=1: thread exiting with uncaught exception (group=0xb0e8d648)
05-26 19:43:22.015: E/AndroidRuntime(2042): FATAL EXCEPTION: main
05-26 19:43:22.015: E/AndroidRuntime(2042): java.lang.SecurityException: Permission Denial: starting Intent { act=android.intent.action.CALL dat=tel:xxx cmp=com.android.phone/.OutgoingCallBroadcaster } from ProcessRecord{b1362a50 2042:com.wuyudong.dial/u0a10047} (pid=2042, uid=10047) requires android.permission.CALL_PHONE
05-26 19:43:22.015: E/AndroidRuntime(2042): at android.os.Parcel.readException(Parcel.java:1431)
05-26 19:43:22.015: E/AndroidRuntime(2042): at android.os.Parcel.readException(Parcel.java:1385)
05-26 19:43:22.015: E/AndroidRuntime(2042): at android.app.ActivityManagerProxy.startActivity(ActivityManagerNative.java:1947)
05-26 19:43:22.015: E/AndroidRuntime(2042): at android.app.Instrumentation.execStartActivity(Instrumentation.java:1419)
05-26 19:43:22.015: E/AndroidRuntime(2042): at android.app.Activity.startActivityForResult(Activity.java:3390)
05-26 19:43:22.015: E/AndroidRuntime(2042): at android.app.Activity.startActivityForResult(Activity.java:3351)
05-26 19:43:22.015: E/AndroidRuntime(2042): at android.app.Activity.startActivity(Activity.java:3587)
05-26 19:43:22.015: E/AndroidRuntime(2042): at android.app.Activity.startActivity(Activity.java:3555)
05-26 19:43:22.015: E/AndroidRuntime(2042): at com.wuyudong.dial.MainActivity$MyListener.onClick(MainActivity.java:44)
05-26 19:43:22.015: E/AndroidRuntime(2042): at android.view.View.performClick(View.java:4240)
05-26 19:43:22.015: E/AndroidRuntime(2042): at android.view.View$PerformClick.run(View.java:17721)
05-26 19:43:22.015: E/AndroidRuntime(2042): at android.os.Handler.handleCallback(Handler.java:730)
05-26 19:43:22.015: E/AndroidRuntime(2042): at android.os.Handler.dispatchMessage(Handler.java:92)
05-26 19:43:22.015: E/AndroidRuntime(2042): at android.os.Looper.loop(Looper.java:137)
05-26 19:43:22.015: E/AndroidRuntime(2042): at android.app.ActivityThread.main(ActivityThread.java:5103)
05-26 19:43:22.015: E/AndroidRuntime(2042): at java.lang.reflect.Method.invokeNative(Native Method)
05-26 19:43:22.015: E/AndroidRuntime(2042): at java.lang.reflect.Method.invoke(Method.java:525)
05-26 19:43:22.015: E/AndroidRuntime(2042): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
05-26 19:43:22.015: E/AndroidRuntime(2042): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
05-26 19:43:22.015: E/AndroidRuntime(2042): at dalvik.system.NativeStart.main(Native Method)

拋出安全異常，提示沒有許可權

解決辦法如下：

打開 AndroidManifest.xml文件

點擊Add，選擇Users Permission

右邊下拉單選擇：android.permission.CALL_PHONE

Ctrl+S

重新運行，搞定