我的Android应用程序中有水平滚动视图,带有下一个和上一个按钮.我想仅在scollview需要滚动时显示这些按钮.滚动视图内容的宽度超出显示宽度.还要在到达第一个时隐藏上一个和下一个按钮最后的项目.点击这些按钮后如何下一个/上一个项目？
main.xml中
IoUs"
android:visibility="gone" />
活动
public class SampleActivity extends Activity {
private static LinearLayout linearLayout;
private static HorizontalScrollView horizontalScrollView;
private static Button btnPrevIoUs;
private static Button btnNext;
private static int displayWidth = 0;
private static int arrowWidth = 0;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
horizontalScrollView = (HorizontalScrollView) findViewById(R.id.horizontalScrollView1);
linearLayout = (LinearLayout) findViewById(R.id.linearLayout1);
btnPrevIoUs = (Button) findViewById(R.id.btnPrevoius);
btnNext = (Button) findViewById(R.id.btnNext);
for (int i = 0; i < 15; i++) {
Button button = new Button(this);
button.setTag(i);
button.setText("---");
linearLayout.addView(button);
}
ViewTreeObserver vto = linearLayout.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
ViewTreeObserver obs = linearLayout.getViewTreeObserver();
obs.removeGlobalOnLayoutListener(this);
Display display = getWindowManager().getDefaultDisplay();
displayWidth = display.getWidth();
if (linearLayout.getMeasuredWidth() > (displayWidth - 40)) {
btnPrevIoUs.setVisibility(View.VISIBLE);
btnNext.setVisibility(View.VISIBLE);
}
}
});
btnPrevIoUs.setOnClickListener(listnerLeftArrowButton);
horizontalScrollView.setOnTouchListener(listenerScrollViewTouch);
}
private OnTouchListener listenerScrollViewTouch = new OnTouchListener() {
@Override
public boolean onTouch(View v,MotionEvent event) {
showHideViews();
return false;
}
};
private OnClickListener listnerLeftArrowButton = new OnClickListener() {
@Override
public void onClick(View v) {
horizontalScrollView.onKeyDown(KeyEvent.KEYCODE_DPAD_RIGHT,new KeyEvent(0,0));
}
};
public static void showHideViews() {
int maxScrollX = horizontalScrollView.getChildAt(0).getMeasuredWidth()- displayWidth;
Log.e("TestProjectActivity","scroll X = " +horizontalScrollView.getScrollX() );
Log.i("TestProjectActivity","scroll Width = " +horizontalScrollView.getMeasuredWidth() );
Log.d("TestProjectActivity","Max scroll X = " + maxScrollX);
if (horizontalScrollView.getScrollX() == 0) {
hideLeftArrow();
} else {
showLeftArrow();
}
if (horizontalScrollView.getScrollX() == maxScrollX) {
showRightArrow();
} else {
//hideRightArrow();
}
}
private static void hideLeftArrow() {
btnPrevIoUs.setVisibility(View.GONE);
}
private static void showLeftArrow() {
btnPrevIoUs.setVisibility(View.VISIBLE);
}
private static void hideRightArrow() {
btnNext.setVisibility(View.GONE);
}
private static void showRightArrow() {
btnNext.setVisibility(View.VISIBLE);
}
}
‘maxScrollX’值对我来说不正确.如何为此找到最大的滚动值？
提前致谢
最佳答案
