Handler实现验证码获取倒计时功能

       最近在项目中，做了绑定手机这一块，接触到了验证码获取倒计时的功能，现在拿出来共享一下。

        handler 里面有个final boolean sendMessageDelayed(Message msg,long delayMilis):指定多少毫秒之后发送消息。这个延时发送消息的方法，可以实现定时的效果，废话少说，上demo.

xml中，定义一个TextView，可以设置它的选中态与背景布局

<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"
              android:orientation="vertical"
    >
    <TextView
        android:id="@+id/tv_handler_message"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:paddingTop="10dp"
        android:paddingBottom="10dp"
        android:paddingLeft="5dp"
        android:paddingRight="5dp"
        android:background="@drawable/selector_six2five_corner5"
        android:text="@string/get_verify_code"/>

</LinearLayout>

选中态布局

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:state_selected="true">
        <shape
            android:shape="rectangle">
            <!-- 矩形的圆角半径 -->
            <corners
                android:radius="5dp"
              />
            <!-- 填充颜色 -->
            <solid android:color="@color/fiveColor"></solid>
            <stroke
                android:width="1dp"
                android:color="@color/fiveColor"/>
        </shape>
    </item>
    <item android:state_focused="true">
        <shape
            android:shape="rectangle">
            <!-- 矩形的圆角半径 -->
            <corners
                android:radius="5dp"/>
            <!-- 填充颜色 -->
            <solid android:color="@color/fiveColor"></solid>
            <stroke
                android:width="1dp"
                android:color="@color/fiveColor"/>
        </shape>
    </item>
    <item android:state_pressed="true">
        <shape
            android:shape="rectangle">
            <!-- 矩形的圆角半径 -->
            <corners
                android:radius="5dp"/>
            <!-- 填充颜色 -->
            <solid android:color="@color/fiveColor"></solid>
            <stroke
                android:width="1dp"
                android:color="@color/fiveColor"/>
        </shape>
    </item>
    <item>
        <shape
            android:shape="rectangle">
            <!-- 矩形的圆角半径 -->
            <corners
                android:radius="5dp"/>
            <!-- 填充颜色 -->
            <solid android:color="@color/sixColor"></solid>
            <stroke
                android:width="1dp"
                android:color="@color/sixColor"/>
        </shape>
    </item>
</selector>

颜色值

<!--灰色-->
<color name="fiveColor">#b4b4b4</color>

<!--红色-->
<color name="sixColor">#e94737</color>

string 文件

<string name="verify_code">获取验证码(%1$s)</string>
<string name="format_get_verify_code">重新获取(%1$s)</string>

代码

public class CountDownActivity extends Activity {
    private TextView tvHandler;
    private static final long DELAY_MILLIS = 1000;//一秒发送一次消息
    private int startTime = 60;//60秒倒计时
    private Handler handler = new Handler(new Handler.Callback() {
        @Override
        public boolean handleMessage(Message msg) {
            startTime--;
            if (startTime == 0) {
                tvHandler.setEnabled(true);//设置按钮可点
                tvHandler.setSelected(false);
                handler.removeMessages(0);//停止
                tvHandler.setText(R.string.get_verify_code);
                startTime = 60;//时间重置
            } else {
                handler.sendMessageDelayed(Message.obtain(handler, 0), DELAY_MILLIS);
                tvHandler.setText(getString(R.string.format_get_verify_code, startTime));
            }
            return true;
        }
    });

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_handler);
        tvHandler = (TextView) findViewById(R.id.tv_handler_message);
        tvHandler.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                tvHandler.setEnabled(false);//设置按钮不可点,字体变灰
                tvHandler.setSelected(true);//被选中后背景变暗
                handler.sendMessageDelayed(Message.obtain(handler, 0), DELAY_MILLIS);//发送延时消息，实现定时效果
            }
        });
    }
}