多个按钮左右相互挤压效果

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal" >
    <LinearLayout 
        android:id="@+id/main_contain"
        android:layout_marginTop="50dp"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:orientation="horizontal"
        android:layout_centerInParent="true" >
        <Button
            android:id="@+id/btnOne"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:text="one" />
        <Button
            android:id="@+id/btnTwo"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:text="two" />
        <Button
            android:id="@+id/btnThree"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:text="three" />
        <Button
            android:id="@+id/btnFour"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:text="four" />
    </LinearLayout>
</RelativeLayout>

package com.example.xinxindemo;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup.LayoutParams;
import android.widget.Button;
import android.widget.LinearLayout;

public class PinchActivity extends Activity implements View.OnClickListener {

    private final static String TAG = "PinchActivity";
    // 屏幕宽度
    private int screentWidth = 0;
    // View可伸展最长的宽度
    private int maxWidth;
    // View可伸展最小宽度
    private int minWidth;
    // 当前点击的View
    private View currentView;
    // 显示最长的那个View
    private View preView;
    // 主布局ViewGroup
    private LinearLayout mainContain;
    // 标识符 动画是否结束
    private boolean animationIsEnd = true;
    // 变大操作
    private static final int OPE_BIG = 1;
    // 变小操作
    private static final int OPE_SMALL = 2;
    // 当前操作 -1表示无效操作
    private int currentOpe = -1;
    // 前进的步伐距离
    private static final int STEP = 10;

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

        initCommonData();
        initViewData();
        measureWidth(screentWidth);
    }

    private void initViewData() {
        mainContain = (LinearLayout) this.findViewById(R.id.main_contain);
        View child;
        int childCount = mainContain.getChildCount();
        for (int i = 0; i < childCount; i++) {
            child = mainContain.getChildAt(i);
            child.setOnClickListener(this);
        }
    }

    private void initCommonData() {
        DisplayMetrics metric = new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getMetrics(metric);
        // 屏幕宽度（像素）
        screentWidth = metric.widthPixels; 
    }

    private void setCurrentViewParams() {
        if (currentView == null) {
            return;
        }
        LayoutParams params = currentView.getLayoutParams();
        if (params == null) {
            return;
        }
        int realWidth = params.width;
        int nextWidth = 0;
        if (currentOpe == OPE_BIG) {
            nextWidth = realWidth + STEP;
        } else if (currentOpe == OPE_SMALL) {
            nextWidth = realWidth - STEP;
        }
        if (nextWidth > maxWidth) {
            nextWidth = maxWidth;
        } else if (nextWidth < minWidth) {
            nextWidth = minWidth;
        }
        params.width = nextWidth;
        currentView.setLayoutParams(params);
        if (nextWidth == maxWidth || nextWidth == minWidth) {
            animationIsEnd = true;
            onOffClickable();
            stopAnimation();
            return;
        }
        mHandler.sendEmptyMessageDelayed(1, 20);
    }

    // 初始化宽度 测量max min 长度
    private void measureWidth(int screenWidth) {
        int halfWidth = screenWidth / 2;
        maxWidth = halfWidth - 50;
        minWidth = (screenWidth - maxWidth) / (mainContain.getChildCount() - 1);

        View child;
        int childCount = mainContain.getChildCount();
        for (int i = 0; i < childCount; i++) {
            child = mainContain.getChildAt(i);
            LayoutParams params = child.getLayoutParams();
            if (i == 0) {
                preView = child;
                params.width = maxWidth;
            } else {
                params.width = minWidth;
            }
            child.setLayoutParams(params);
        }
    }

    // 这里用handler更新界面
    private Handler mHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            if (msg.what == 1) {
                setCurrentViewParams();
            }
        }
    };

    // 停止动画
    private void stopAnimation() {
        currentOpe = -1;
        currentView = null;
    }

    private void startAnimation() {
        if (currentView == null || currentOpe == -1) {
            Log.d(TAG, "无效动画");
            return;
        }
        animationIsEnd = false;
        onOffClickable();
        mHandler.sendEmptyMessage(1);
    }

    @Override
    public void onClick(View v) {
        int id = v.getId();
        switch (id) {
        case R.id.btnOne:
            currentView = mainContain.getChildAt(0);
            break;
        case R.id.btnTwo:
            currentView = mainContain.getChildAt(1);
            break;
        case R.id.btnThree:
            currentView = mainContain.getChildAt(2);
            break;
        case R.id.btnFour:
            currentView = mainContain.getChildAt(3);
            break;
        }

        Log.i(TAG, ((Button) currentView).getText().toString() + " click");

        if (currentView != null && animationIsEnd) {
            int currentViewWidth = currentView.getWidth();
            if (currentViewWidth == maxWidth) {
                currentOpe = OPE_SMALL;
            } else {
                currentOpe = OPE_BIG;
            }
            clickEvent(currentView);
            startAnimation();
        }

    }

    private void clickEvent(View view) {
        View child;
        int childCount = mainContain.getChildCount();
        for (int i = 0; i < childCount; i++) {
            child = mainContain.getChildAt(i);
            if (preView == child) {
                LinearLayout.LayoutParams params = (android.widget.LinearLayout.LayoutParams) child
                        .getLayoutParams();
                params.weight = 1.0f;
                child.setLayoutParams(params);
            } else {
                LinearLayout.LayoutParams params = (android.widget.LinearLayout.LayoutParams) child
                        .getLayoutParams();
                params.weight = 0.0f;
                params.width = minWidth;
                child.setLayoutParams(params);
            }
        }
        preView = view;
        printWeight();
    }

    private void printWeight() {
        View child;
        int childCount = mainContain.getChildCount();
        for (int i = 0; i < childCount; i++) {
            child = mainContain.getChildAt(i);
            LinearLayout.LayoutParams params = (android.widget.LinearLayout.LayoutParams) child
                    .getLayoutParams();
            Log.i("mm1", ((Button) child).getText() + ": " + params.weight);
        }
    }

    //
    private void onOffClickable() {
        View child;
        boolean clickable = animationIsEnd;
        int childCount = mainContain.getChildCount();
        for (int i = 0; i < childCount; i++) {
            child = mainContain.getChildAt(i);
            child.setClickable(clickable);
        }
    }

}