Android

Android 三屏左右滑动切换的实现

Nitro Hsu

Mar 12, 2013 • 2 min read

实现原理：

将三个界面放置于FrameLayout中，默认显示当前主页面,左(右)滑动，显示左(右)辅页面，隐藏右(左)辅页面,根据滑动距离重绘主页面在屏幕的位置。当用户滑动停止抬起手指时，判断总计滑动距离，若大于屏幕宽度1/2，直接定位到主页面偏移结果位置处。

package com.n2hsu.n2flipper;

import android.os.Bundle;
import android.view.GestureDetector;
import android.view.GestureDetector.OnGestureListener;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.FrameLayout;
import android.widget.RelativeLayout;
import android.app.Activity;

public class MainActivity extends Activity implements OnTouchListener, OnGestureListener {

private RelativeLayout mLeft = null;
private RelativeLayout mMain = null;
private RelativeLayout mRight = null;
private GestureDetector mGestureDetector;
//
private int mWidth = 0;
private int mHeight = 0;

private final int mOverlapX = 100;
private float mDistanceSum = 0;
private final int mTimes = 2;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

mLeft = (RelativeLayout) findViewById(R.id.left);
mMain = (RelativeLayout) findViewById(R.id.main_view);
mRight = (RelativeLayout) findViewById(R.id.right);

mGestureDetector = new GestureDetector(this);

mWidth = this.getResources().getDisplayMetrics().widthPixels;
mHeight = this.getResources().getDisplayMetrics().heightPixels;

mMain.setOnTouchListener(this);
mMain.setLongClickable(true);

FrameLayout.LayoutParams layout = new FrameLayout.LayoutParams(mWidth, mHeight);
mMain.setLayoutParams(layout);
mLeft.setLayoutParams(layout);
mRight.setLayoutParams(layout);

}

@Override
public boolean onDown(MotionEvent e) {
return false;
}

@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {

return false;
}

@Override
public void onLongPress(MotionEvent e) {
}

@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {

float distance = e2.getAxisValue(MotionEvent.AXIS_X) - e1.getAxisValue(MotionEvent.AXIS_X);

mDistanceSum += distance;
// X offset
mMain.layout((int) (mMain.getX() + distance), 0, (int) (mMain.getX() + distance + mWidth), mHeight);
// view visible or invisible
if (mMain.getX() >= 0) {
mRight.setVisibility(View.GONE);
mLeft.setVisibility(View.VISIBLE);
} else {
mLeft.setVisibility(View.GONE);
mRight.setVisibility(View.VISIBLE);
}
return true;
}

@Override
public void onShowPress(MotionEvent e) {
}

@Override
public boolean onSingleTapUp(MotionEvent e) {
return false;
}

@Override
public boolean onTouch(View v, MotionEvent event) {

if (event.getAction() == MotionEvent.ACTION_DOWN) {
// init scroll distance
mDistanceSum = 0;
}
if (event.getAction() == MotionEvent.ACTION_UP) {

if (Math.abs(mDistanceSum) > mWidth / mTimes) {
if (mMain.getX() > 0) {
mMain.layout(mWidth - mOverlapX, 0, mWidth - mOverlapX + mWidth, mHeight);
} else {
mMain.layout(mOverlapX - mWidth, 0, mOverlapX, mHeight);
}
} else {
// restore initial status
mMain.layout(0, 0, mWidth, mHeight);
mRight.setVisibility(View.GONE);
mLeft.setVisibility(View.GONE);
}
}

return mGestureDetector.onTouchEvent(event);
}
}

资源文件：