在電商類app的購物車頁面,經常會有這樣的需求:長按“+”按鈕或者“-”按鈕時,購物車中的商品數量連續的增加或減少。
本例的目的就是爲了實現這個效果。預覽圖:
1.自定義Button.
/**
* 長按連續響應的Button
* Created by admin on 15-6-1.
*/
public class LongClickButton extends Button {
/**
* 長按連續響應的監聽,長按時將會多次調用該接口中的方法直到長按結束
*/
private LongClickRepeatListener repeatListener;
/**
* 間隔時間(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();
}
/**
* 初始化監聽
*/
private void init() {
handler = new MyHandler(this);
setOnLongClickListener(new OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
new Thread(new LongClickThread()).start();
return true;
}
});
}
/**
* 長按時,該線程將會啓動
*/
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);
}
}
}
/**
* 通過handler,使監聽的事件響應在主線程中進行
*/
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();
}
}
}
/**
* 設置長按連續響應的監聽和間隔時間,長按時將會多次調用該接口中的方法直到長按結束
*
* @param listener 監聽
* @param intervalTime 間隔時間(ms)
*/
public void setLongClickRepeatListener(LongClickRepeatListener listener, long intervalTime) {
this.repeatListener = listener;
this.intervalTime = intervalTime;
}
/**
* 設置長按連續響應的監聽(使用默認間隔時間100ms),長按時將會多次調用該接口中的方法直到長按結束
*
* @param listener 監聽
*/
public void setLongClickRepeatListener(LongClickRepeatListener listener) {
setLongClickRepeatListener(listener, 100);
}
public interface LongClickRepeatListener {
void repeatAction();
}
}
2.在Activity中調用:
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);
//連續減
buttonSub.setLongClickRepeatListener(new LongClickButton.LongClickRepeatListener() {
@Override
public void repeatAction() {
numberTV.setText(String.valueOf(Integer.parseInt(numberTV.getText().toString()) - 1));
}
}, 50);
//連續加
buttonAdd.setLongClickRepeatListener(new LongClickButton.LongClickRepeatListener() {
@Override
public void repeatAction() {
numberTV.setText(String.valueOf(Integer.parseInt(numberTV.getText().toString()) + 1));
}
}, 50);
//減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.很多時候,長按的事件和普通點擊的事件是一樣的(也就是說,長按相當於連續的快速點擊)。這種情況下,自定義Button可以更加簡潔:即在長按時,連續的調用普通的OnClickListener。
public class LongClickButton2 extends Button {
/**
* 間隔時間(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();
}
/**
* 初始化監聽
*/
private void init() {
handler = new MyHandler(this);
setOnLongClickListener(new OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
new Thread(new LongClickThread()).start();
return true;
}
});
}
/**
* 長按時,該線程將會啓動
*/
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);
}
}
}
/**
* 通過handler,使監聽的事件響應在主線程中進行
*/
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) {
//直接調用普通點擊事件
button.performClick();
}
}
}
public void setIntervalTime(long intervalTime) {
this.intervalTime = intervalTime;
}
}