我有一个带有 TableLayout 的 android 应用程序，每行都有一个 SeekBar 和一个 ToggleButton。这些行超出了屏幕的可见范围，因此可以滚动。当我触摸并拖动以向上滚动页面并在此过程中触摸 SeekBar 时，它会立即更改“拇指”的位置，而不是滚动页面。但是，ToggleButton 的行为并非如此；相反，我可以开始拖动按钮并滚动然后释放，而不会改变 ToggleButton 的状态。
有没有办法让 SeekBar 以这种方式运行，这样触摸它开始拖动不会导致栏改变位置而是滚动页面？
【问题讨论】：
我也遇到过类似的问题。我能找到的唯一解决方案（当搜索栏在列表视图中时）是禁用搜索栏，直到单击该项目。
在 ArrayAdapter 中，我将 enabled 和 focusable 都设置为 false 并添加了 SeekBar 侦听器，将属性设置为 false 允许我使用列表项 onItemClicked 侦听器。在 onItemCLickListener 中，我检索了搜索栏，将属性设置为 true，这意味着它可以向上或向下滑动。然后我在调整后禁用它。代码如下
此代码在列表项的创建中，其中包含搜索栏
seekBar.setClickable(false);
seekBar.setFocusable(false);
seekBar.setEnabled(false);
/* attach listener */
attachProgressUpdatedListener(seekBar, positionOfItemInList);
此方法将侦听器附加到数组适配器类中的搜索栏
private void attachProgressUpdatedListener(SeekBar seekBar,
final int position) {
seekBar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
public void onStopTrackingTouch(SeekBar seekBar) {
int progress = seekBar.getProgress();
int task_id = (Integer) seekBar.getTag();
TaskHandler taskHandler = new TaskHandler(DBAdapter
.getDBAdapterInstance(getContext()));
taskHandler.updateTaskProgress(task_id, progress);
mList.get(position).setProgress(progress);
//need to fire an update to the activity
notifyDataSetChanged();
seekBar.setEnabled(false);
}
public void onStartTrackingTouch(SeekBar seekBar) {
// empty as onStartTrackingTouch listener not being used in
// current implementation
}
public void onProgressChanged(SeekBar seekBar, int progress,
boolean fromUser) {
// empty as onProgressChanged listener not being used in
// current implementation
}
});
}
此片段来自包含列表视图的活动。
taskListView.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
SeekBar sb = (SeekBar) view.findViewById(R.id.seek);
sb.setFocusable(true);
sb.setEnabled(true);
}
});
【讨论】：
我通过对搜索栏进行子类化并检查运动角度是否大于 45 度来使其工作。在这种情况下，忽略触摸并返回 false，以便滚动视图执行其操作。
编辑：
这是一个扩展的 SeekBar，它允许您在浮点数而不是整数中设置最小值/最大值。
public class SeekBarEx extends SeekBar implements
SeekBar.OnSeekBarChangeListener {
final int SEEK_POINTS = 0x10000;
final String TAG = "SeekBarEx";
public float mMax;
public float mMin;
public OnSeekBarExChangeListener delegate = null;
public interface OnSeekBarExChangeListener {
public void onSeekChanged(SeekBarEx seekBarEx, float value,
boolean fromUser);
public void onStartTrackingTouch(SeekBarEx seekBar);
public void onStopTrackingTouch(SeekBarEx seekBar);
}
public SeekBarEx(Context ctx, AttributeSet attr) {
super(ctx, attr);
super.setMax(SEEK_POINTS);
mMin = 0f;
mMax = 1.0f;
initAttributes(attr);
this.setOnSeekBarChangeListener(this);
}
public void setDelegate(OnSeekBarExChangeListener d) {
delegate = d;
}
public void initAttributes(AttributeSet attrSet) {
TypedArray a;
a = getContext().obtainStyledAttributes(attrSet, R.styleable.SeekBarEx);
final int N = a.getIndexCount();
int i;
for (i = 0; i < N; i++) {
int attr = a.getIndex(i);
switch (attr) {
case R.styleable.SeekBarEx_max:
mMax = a.getFloat(i, 1.0f);
Log.d(TAG, "maxSet " + mMax);
break;
case R.styleable.SeekBarEx_min:
mMin = a.getFloat(i, 0f);
Log.d(TAG, "minSet" + mMin);
break;
case R.styleable.SeekBarEx_value:
this.setValue(a.getFloat(i, 0));
break;
}
}
a.recycle();
}
@Override
public int getProgress() {
return super.getProgress();
}
public float getValue() {
float r;
float run;
r = (float) super.getProgress();
r = r / (float) SEEK_POINTS;
run = mMax - mMin;
r = r * run + mMin;
return r;
}
public void setValue(float v) {
if (Float.isNaN(v) || Float.isInfinite(v))
return;
if (v > mMax)
v = mMax;
if (v < mMin)
v = mMin;
float run;
int setv;
run = mMax - mMin;
v -= mMin;
setv = Math.round(v * (float) SEEK_POINTS / run);
super.setProgress(setv);
}
public boolean valueChanged = false;
public void cancelTracking() {
if (oldValue != Float.NaN) {
this.setValue(oldValue);
oldValue = Float.NaN;
valueChanged = false;
acceptTouches = false;
acceptChange = false;
}
}
// we override these methods so that when we forcully cancel
// on ontouches moved. We can revert back to the old value
@Override
public void onProgressChanged(SeekBar seekBar, int progress,
boolean fromUser) {
Log.d(TAG, "SeekBar changed to " + progress);
if (delegate != null && acceptTouches) {
valueChanged = true;
delegate.onSeekChanged(this, this.getValue(), fromUser);
} else
cancelTracking();
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
if (delegate != null)
delegate.onStartTrackingTouch(this);
}
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
if (delegate != null && valueChanged)
delegate.onStopTrackingTouch(this);
else
cancelTracking();
acceptChange = false;
valueChanged = false;
}
public float mY, mX;
public boolean acceptTouches = true;
// acceptChange never read todo: delete
public boolean acceptChange = false;
public float oldValue = Float.NaN;
public ScrollView getScrollView() {
View view;
view = this;
int maxUp;
maxUp = 5;
while (view != null && maxUp > 0) {
view = (View) view.getParent();
ScrollView scroller;
if (view instanceof ScrollView) {
scroller = (ScrollView) view;
return scroller;
}
maxUp--;
}
return null;
}
// **************************************
// This is the important part in achieving the effect in scroll
// view to be nice
@Override
public boolean onTouchEvent(MotionEvent event) {
int action;
action = event.getAction() & MotionEvent.ACTION_MASK;
ScrollView scroller = this.getScrollView();
boolean mayScroll;
mayScroll = true;
if (scroller == null)
mayScroll = false;
else {
int scrollAmount = scroller.getMaxScrollAmount();
if (scrollAmount == 0)
mayScroll = false;
}
switch (action) {
case MotionEvent.ACTION_CANCEL:
Log.d(TAG, "got cancel touches");
cancelTracking();
super.onTouchEvent(event);
return true;
case MotionEvent.ACTION_DOWN:
mX = event.getX();
mY = event.getY();
acceptTouches = true;
acceptChange = false;
oldValue = this.getValue();
valueChanged = false;
break;
case MotionEvent.ACTION_MOVE:
float x;
float y;
x = event.getX();
y = event.getY();
float dx;
float dy;
dx = x - mX;
dy = y - mY;
if (dx < 0)
dx = -dx;
if (dy < 0)
dy = -dy;
y = this.getHeight() / 2 - y;
float angle;
float distance;
distance = dx * dx + dy * dy;
// I just realized this is wrong it should be
// angle = (float)Math.acos(Math.abs(dx)/Math.sqrt(distance))
// I'm leaving it until tested or someone can confirm
angle = (float) Math.atan(dy / dx);
int distanceLimit;
distanceLimit = this.getHeight() / 3;
distanceLimit *= distanceLimit;
// if we move at an angle of atleast 45degrees
// cancel
if (mayScroll && angle > Math.PI / 4.0) {
cancelTracking();
}
mX += 100000;
if (y < 0)
y = -y;
// if we moved finger too far just cancel
// cause the person may have wanted to scroll but
// failed so we revert back to the old value
if (y > this.getHeight() * 2) {
cancelTracking();
} else if (acceptTouches)
acceptChange = true;
break;
default:
break;
}
// if we accept touches do the usual otherwise
// return false so scrollView can do it's thing
if (acceptTouches)
return super.onTouchEvent(event);
return false;
}
}
seekbarex.xml 如下所示。这只是将 min/max/value 添加为浮点数。
<declare-styleable name="SeekBarEx">
<attr name="min" format="float"/>
<attr name="max" format="float"/>
<attr name="value" format="float"/>
</declare-styleable>
</resources>
【讨论】：