Android：长按连续响应的Button

在电商类app的购物车页面，经常会有这样的需求：长按“+”按钮或者“-”按钮时，购物车中的商品数量连续的增加或减少。

本例的目的就是为了实现这个效果。预览图：



1.自定义Button.

/**
* 长按连续响应的Button
* Created by admin on 15-6-1.
*/
public class LongClickButton extends Button {
/**
* 长按连续响应的监听，长按时将会多次调用该接口中的方法直到长按结束
*/
private LongClickRepeatListener repeatListener;
/**
* 间隔时间（ms）
*/
private long intervalTime;

private MyHandler handler;

public LongClickButton(Context context) {
super(context);

init();
}

public LongClickButton(Context context, AttributeSet attrs) {
super(context, attrs);

init();
}

public LongClickButton(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);

init();
}

/**
* 初始化监听
*/
private void init() {
handler = new MyHandler(this);
setOnLongClickListener(new OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
new Thread(new LongClickThread()).start();
return true;
}
});
}

/**
* 长按时，该线程将会启动
*/
private class LongClickThread implements Runnable {
private int num;

@Override
public void run() {
while (LongClickButton.this.isPressed()) {
num++;
if (num % 5 == 0) {
handler.sendEmptyMessage(1);
}

SystemClock.sleep(intervalTime / 5);
}
}
}

/**
* 通过handler，使监听的事件响应在主线程中进行
*/
private static class MyHandler extends Handler {
private WeakReference<LongClickButton> ref;

MyHandler(LongClickButton button) {
ref = new WeakReference<>(button);
}

@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);

LongClickButton button = ref.get();
if (button != null && button.repeatListener != null) {
button.repeatListener.repeatAction();
}
}
}

/**
* 设置长按连续响应的监听和间隔时间，长按时将会多次调用该接口中的方法直到长按结束
*
* @param listener     监听
* @param intervalTime 间隔时间（ms）
*/
public void setLongClickRepeatListener(LongClickRepeatListener listener, long intervalTime) {
this.repeatListener = listener;
this.intervalTime = intervalTime;
}

/**
* 设置长按连续响应的监听（使用默认间隔时间100ms），长按时将会多次调用该接口中的方法直到长按结束
*
* @param listener 监听
*/
public void setLongClickRepeatListener(LongClickRepeatListener listener) {
setLongClickRepeatListener(listener, 100);
}

public interface LongClickRepeatListener {
void repeatAction();
}
}

2.在Activity中调用：

LongClickButton buttonSub = (LongClickButton) findViewById(R.id.long_click_button1);
LongClickButton buttonAdd = (LongClickButton) findViewById(R.id.long_click_button2);
final TextView numberTV = (TextView) findViewById(R.id.main_number);

//连续减
buttonSub.setLongClickRepeatListener(new LongClickButton.LongClickRepeatListener() {
@Override
public void repeatAction() {
numberTV.setText(String.valueOf(Integer.parseInt(numberTV.getText().toString()) - 1));
}
}, 50);
//连续加
buttonAdd.setLongClickRepeatListener(new LongClickButton.LongClickRepeatListener() {
@Override
public void repeatAction() {
numberTV.setText(String.valueOf(Integer.parseInt(numberTV.getText().toString()) + 1));
}
}, 50);

//减1
buttonSub.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
numberTV.setText(String.valueOf(Integer.parseInt(numberTV.getText().toString()) - 1));
}
});
//加1
buttonAdd.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
numberTV.setText(String.valueOf(Integer.parseInt(numberTV.getText().toString()) + 1));
}
});

3.很多时候，长按的事件和普通点击的事件是一样的（也就是说，长按相当于连续的快速点击）。这种情况下，自定义Button可以更加简洁：即在长按时，连续的调用普通的OnClickListener。

public class LongClickButton2 extends Button {
/**
* 间隔时间（ms）
*/
private long intervalTime = 50;

private MyHandler handler;

public LongClickButton2(Context context) {
super(context);

init();
}

public LongClickButton2(Context context, AttributeSet attrs) {
super(context, attrs);

init();
}

public LongClickButton2(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);

init();
}

/**
* 初始化监听
*/
private void init() {
handler = new MyHandler(this);
setOnLongClickListener(new OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
new Thread(new LongClickThread()).start();
return true;
}
});
}

/**
* 长按时，该线程将会启动
*/
private class LongClickThread implements Runnable {
private int num;

@Override
public void run() {
while (LongClickButton2.this.isPressed()) {
num++;
if (num % 5 == 0) {
handler.sendEmptyMessage(1);
}

SystemClock.sleep(intervalTime / 5);
}
}
}

/**
* 通过handler，使监听的事件响应在主线程中进行
*/
private static class MyHandler extends Handler {
private WeakReference<LongClickButton2> ref;

MyHandler(LongClickButton2 button) {
ref = new WeakReference<>(button);
}

@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);

LongClickButton2 button = ref.get();
if (button != null) {
//直接调用普通点击事件
button.performClick();
}
}
}

public void setIntervalTime(long intervalTime) {
this.intervalTime = intervalTime;
}
}