如何使用ViewPager
等最新工具实现与GitHub中的用户界面和代码相同的功能。创建的代码还没有使用最新的工具开发。对我来说,它似乎有点困难。
有什么建议吗?
答案 0 :(得分:1)
试试这个
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.example.pagercontainer.PagerContainer
android:id="@+id/pager_container"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#CCC">
<android.support.v4.view.ViewPager
android:layout_width="150dp"
android:layout_height="100dp"
android:layout_gravity="center_horizontal" />
</com.example.pagercontainer.PagerContainer>
</RelativeLayout>
PagerActivity.java
import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
/**
* PagerActivity: A Sample Activity for PagerContainer
*/
public class PagerActivity extends Activity {
PagerContainer mContainer;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mContainer = (PagerContainer) findViewById(R.id.pager_container);
ViewPager pager = mContainer.getViewPager();
PagerAdapter adapter = new MyPagerAdapter();
pager.setAdapter(adapter);
//Necessary or the pager will only have one extra page to show
// make this at least however many pages you can see
pager.setOffscreenPageLimit(adapter.getCount());
//A little space between pages
pager.setPageMargin(15);
//If hardware acceleration is enabled, you should also remove
// clipping on the pager for its children.
pager.setClipChildren(false);
}
//Nothing special about this adapter, just throwing up colored views for demo
private class MyPagerAdapter extends PagerAdapter {
@Override
public Object instantiateItem(ViewGroup container, int position) {
TextView view = new TextView(PagerActivity.this);
view.setText("Item "+position);
view.setGravity(Gravity.CENTER);
view.setBackgroundColor(Color.argb(255, position * 50, position * 10, position * 50));
container.addView(view);
return view;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView((View)object);
}
@Override
public int getCount() {
return 5;
}
@Override
public boolean isViewFromObject(View view, Object object) {
return (view == object);
}
}
}
PagerContainer .java
import android.content.Context;
import android.graphics.Point;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.FrameLayout;
/**
* PagerContainer: A layout that displays a ViewPager with its children that are outside
* the typical pager bounds.
*/
public class PagerContainer extends FrameLayout implements ViewPager.OnPageChangeListener {
private ViewPager mPager;
boolean mNeedsRedraw = false;
public PagerContainer(Context context) {
super(context);
init();
}
public PagerContainer(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public PagerContainer(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
private void init() {
//Disable clipping of children so non-selected pages are visible
setClipChildren(false);
//Child clipping doesn't work with hardware acceleration in Android 3.x/4.x
//You need to set this value here if using hardware acceleration in an
// application targeted at these releases.
setLayerType(View.LAYER_TYPE_SOFTWARE, null);
}
@Override
protected void onFinishInflate() {
try {
mPager = (ViewPager) getChildAt(0);
mPager.setOnPageChangeListener(this);
} catch (Exception e) {
throw new IllegalStateException("The root child of PagerContainer must be a ViewPager");
}
}
public ViewPager getViewPager() {
return mPager;
}
private Point mCenter = new Point();
private Point mInitialTouch = new Point();
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
mCenter.x = w / 2;
mCenter.y = h / 2;
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
//We capture any touches not already handled by the ViewPager
// to implement scrolling from a touch outside the pager bounds.
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
mInitialTouch.x = (int)ev.getX();
mInitialTouch.y = (int)ev.getY();
default:
ev.offsetLocation(mCenter.x - mInitialTouch.x, mCenter.y - mInitialTouch.y);
break;
}
return mPager.dispatchTouchEvent(ev);
}
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
//Force the container to redraw on scrolling.
//Without this the outer pages render initially and then stay static
if (mNeedsRedraw) invalidate();
}
@Override
public void onPageSelected(int position) { }
@Override
public void onPageScrollStateChanged(int state) {
mNeedsRedraw = (state != ViewPager.SCROLL_STATE_IDLE);
}
}
请参阅this