a Count Down View

CountDownView.java

package me.tikitoo.android.androiddemo;

import android.content.Context;
import android.os.CountDownTimer;
import android.util.AttributeSet;
import android.view.View;
import android.widget.TextView;

/**
 * Created by Tikitoo on 2016/4/3.
 */
public class CountDownView extends TextView implements View.OnClickListener {

    private MyCountTimer mMyCountTimer;

    public CountDownView(Context context) {
        this(context, null);
    }

    public CountDownView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public CountDownView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        setOnClickListener(this);
    }

    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();
    }

    boolean flag = true;

    @Override
    protected void onDetachedFromWindow() {
        super.onDetachedFromWindow();
        if (mMyCountTimer != null) {
            mMyCountTimer.cancel();
        }
    }

    @Override
    public void onClick(View v) {
        if (mMyCountTimer == null) {
            mMyCountTimer = new MyCountTimer(10 * 1000, 1000);
        }
        if (flag) {
            mMyCountTimer.start();
            onStart();
        }
    }

    class MyCountTimer extends CountDownTimer {

        public MyCountTimer(long millisInFuture, long countDownInterval) {
            super(millisInFuture, countDownInterval);
        }

        @Override
        public void onTick(long s) {
            flag = false;
            setText(s / 1000 + "秒");
        }

        @Override
        public void onFinish() {
            flag = true;
            setText("重新发送");
            CountDownView.this.onPost();
        }
    }

    private Callback mCallback;

    public void setCallback(Callback callback) {
        mCallback = callback;
    }

    public void onStart() {
        if (mCallback != null) {
            mCallback.onPre();
        }
    }

    public void onPost() {
        if (mCallback != null) {
            mCallback.onPost();
        }
    }

    public interface Callback {
        void onPre();
        void onPost();
    }
}

MainActivity.java

package me.tikitoo.android.androiddemo;

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

public class MainActivity extends AppCompatActivity implements CountDownView.Callback {

    private CountDownView mCountDownView;

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

        mCountDownView = (CountDownView) findViewById(R.id.count_view);
        mCountDownView.setCallback(this);
    }

    @Override
    public void onPre() {
        mCountDownView.setTextColor(R.color.text_click);
        mCountDownView.setBackgroundResource(R.color.back_click);
        
    }

    @Override
    public void onPost() {
        mCountDownView.setTextColor(R.color.text_already);
        mCountDownView.setBackgroundResource(R.color.back_already);
        Toast.makeText(MainActivity.this, "onFinish", Toast.LENGTH_SHORT).show();
    }
}

CountDownView 是一个自定义的验证码定时器View，它会自动倒计时，并且提供了onPre() 和onPost() 方法，来发送API，和验证码发送结束。下面是预览图