CountDownTimer
项目中经常用到倒计时的功能，比如说限时抢购，手机获取验证码等等。而google官方也帮我们封装好了一个类:CountDownTimer,使我们的开发更加方便。
CountDownTimer是一个抽象类，有两个抽象方法，它的API很简单：
public abstract void onTick(long millisUntilFinished);//这个是每次间隔指定时间的回调，millisUntilFinished：剩余的时间，单位毫秒
public abstract void onFinish();//这个是倒计时结束的回调
实现方式1
CountDownTimeUtil
public class CountDownTimeUtil {
private WeakReference<TextView> tvCodeWr;//控件软引用，防止内存泄漏
private CountDownTimer timer;
private int times = 60 * 1000;
public CountDownTimeUtil(TextView textView) {
super();
this.tvCodeWr = new WeakReference(textView);
}
public void runTimer() {
//倒计时的总时长 每次的间隔时间 单位都是毫秒
timer = new CountDownTimer(times, 1000) {
/**
* 这个是倒计时结束的回调
*/
@Override
public void onFinish() {
if (tvCodeWr.get() != null) {
tvCodeWr.get().setClickable(true);
tvCodeWr.get().setText("重新获取");
tvCodeWr.get().setTextColor(Color.parseColor("#ff0000"));
}
cancel();
}
/**
* 这个是每次间隔指定时间的回调
*
* @param millisUntilFinished 剩余的时间，单位毫秒
*/
@Override
public void onTick(long millisUntilFinished) {
if (tvCodeWr.get() != null) {
tvCodeWr.get().setClickable(false);
tvCodeWr.get().setText(millisUntilFinished / 1000 + "s后重新获取");
tvCodeWr.get().setTextColor(Color.parseColor("#666666"));
}
}
}.start();
}
/**
* 这个方法可以在activity或者fragment销毁的时候调用，防止内存泄漏
* 如果在activity或者fragment关闭销毁的时候没有调用cancle方法，它的onTick方法还是会继续执行，这个时候UI控件都为空，不注意判断的话很容易空指针
*/
public void cancel() {
if (timer != null) {
timer.onFinish();
timer.cancel();
timer = null;
}
}
}
获取验证码按钮布局
<LinearLayout
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_marginHorizontal="20dp"
android:layout_marginTop="50dp"
android:gravity="center_vertical">
<EditText
android:id="@+id/et_verification_code"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="@null"
android:hint="请输入验证码"
android:inputType="number"
android:maxLength="6"
android:textColor="@color/black"
android:textSize="16sp" />
<TextView
android:id="@+id/tv_get_verification_code"
android:layout_width="wrap_content"
android:layout_height="21dp"
android:gravity="center"
android:text="获取验证码"
android:textColor="#ff0000"
android:textSize="14sp" />
</LinearLayout>
使用
public class MainActivity extends AppCompatActivity {
private TextView mTvGetVerificationCode;
private CountDownTimeUtil mCountDownTimeUtil;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTvGetVerificationCode = (TextView) findViewById(R.id.tv_get_verification_code);
mTvGetVerificationCode.setOnClickListener(v -> {
mCountDownTimeUtil = new CountDownTimeUtil(mTvGetVerificationCode);
mCountDownTimeUtil.runTimer();
});
}
@Override
protected void onDestroy() {
super.onDestroy();
if (mCountDownTimeUtil != null) {
mCountDownTimeUtil.cancel();
}
}
}
实现方式2：自定义倒计时控件
CountDownText
/**
* Cerated by xiaoyehai
* Create date : 2020/12/31 14:28
* description : 倒计时控件
*/
public class CountDownText extends AppCompatTextView {
private CountDownTimer mCountDownTimer;
/***
* 持续时间毫秒
*/
private int mTimeDuration ;
/***
* 间隔时间毫秒
*/
private int mTimerGap ;
public CountDownText(Context context) {
this(context, null);
}
public CountDownText(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public CountDownText(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.CountDownText);
mTimeDuration = typedArray.getInt(R.styleable.CountDownText_millisDuration, 5000);
mTimerGap = typedArray.getInt(R.styleable.CountDownText_millisGap, 1000);
typedArray.recycle();
initTimer();
setText("获取验证码");
}
private void initTimer() {
mCountDownTimer = new CountDownTimer(mTimeDuration + 500, mTimerGap) {
@Override
public void onTick(long millisUntilFinished) {
setText(String.format("%ss后重新获取", millisUntilFinished / 1000));
setEnabled(false);
setTextColor(Color.parseColor("#333333"));
}
@Override
public void onFinish() {
setEnabled(true);
setText("重新获取");
setTextColor(Color.parseColor("#ff0000"));
}
};
}
public void start() {
if (mCountDownTimer != null) {
mCountDownTimer.start();
}
}
private void end() {
if (mCountDownTimer != null) {
mCountDownTimer.cancel();
}
}
@Override
protected void onDetachedFromWindow() {
super.onDetachedFromWindow();
end();
mCountDownTimer = null;
}
}
<LinearLayout
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_marginHorizontal="20dp"
android:layout_marginTop="50dp"
android:gravity="center_vertical">
<EditText
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="@null"
android:hint="请输入验证码"
android:inputType="number"
android:maxLength="6"
android:textColor="@color/black"
android:textSize="16sp" />
<com.zly.demo10.widget.CountDownText
android:id="@+id/cdt_get_verification_code"
android:layout_width="wrap_content"
android:layout_height="21dp"
android:enabled="true"
android:gravity="center"
android:textColor="#ff0000"
android:textSize="14sp"
app:millisDuration="60000"
app:millisGap="1000"
tools:text="获取验证码" />
</LinearLayout>
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
CountDownText countDownText = (CountDownText) findViewById(R.id.cdt_get_verification_code);
countDownText.setOnClickListener(v->countDownText.start());
}
}
