使用ViewPager时的OOM问题解决

最近在写项目过程中遇到这样一个问题。一个用viewPager制作的APP启动引导页，其内容只有一个imageView，而且每个imageView的平均为100K左右，该项目在720P手机上运行完全正常。但是在换到1080P手机上运行的时候却给博主抛出了结结实实的一记OOM，顿时让我懵逼不已，问题被锁定在了imageview的setbackgroundresourse()方法中。viewpager中，我用for循环依次创建了4个imageview对象并且依次添加到viewpager所对应的list集合中。如代码中被注释的语句。后为解决该问题，改为在for循环中只是单纯实例化四个imageview对象而原来的setbackgroundresourse()操作被放在了viewpager的

public Object instantiateItem(ViewGroup container, int position) {
imageViews.get(position).setImageResource(imageId[position]);
container.addView(imageViews.get(position));
return imageViews.get(position);
}

中进行。如此之后OOM即可解决。
全部代码如下

package com.example.xiaom.activities;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewTreeObserver;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;

import com.example.xiaom.myplugins.TitleLayout;
import com.example.xiaom.utils.FirstLaunchSharePerenferens;

import java.util.ArrayList;

public class user_first_guide extends Activity {
private static final int []imageId={R.drawable.guide_1,
R.drawable.guide_2,
R.drawable.guide_3,
R.drawable.guide_4};
private ViewPager viewPager;
private ArrayList<ImageView> imageViews;
private Button btn_start;
private LinearLayout linearLayout;
private View point_white;
private int wid;
private RelativeLayout relativeLayout1;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_user_first_guide);
InitView();
setAdapter();
setListener();
}

private void setListener() {
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
RelativeLayout.LayoutParams relativeLayout = (RelativeLayout.LayoutParams) point_white.getLayoutParams();
relativeLayout.leftMargin = (int)(position * wid + wid * positionOffset);
relativeLayout1 = (RelativeLayout) findViewById(R.id.rl_points);
point_white.setLayoutParams(relativeLayout);
}

@Override
public void onPageSelected(int position) {
if (position == imageId.length - 1){
btn_start.setVisibility(View.VISIBLE);

}else {
btn_start.setVisibility(View.INVISIBLE);
}
}

@Override
public void onPageScrollStateChanged(int state) {

}
});
btn_start.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(user_first_guide.this, MainActivity.class);
startActivity(intent);
FirstLaunchSharePerenferens.isFirstLaunch(user_first_guide.this,false);
finish();
}
});

}

private void setAdapter() {
MyViewPagerAdapter myViewPagerAdapter = new MyViewPagerAdapter();
viewPager.setAdapter(myViewPagerAdapter);
}

private void InitView() {
imageViews = new ArrayList<>();
viewPager = (ViewPager) findViewById(R.id.vp_guide);
point_white = findViewById(R.id.guide_point_white);
btn_start = (Button) findViewById(R.id.btn_start);
linearLayout = (LinearLayout) findViewById(R.id.ll_guide_point);
for (int i = 0; i < imageId.length; i ++){
ImageView imageView = new ImageView(this);
//            imageView.setBackgroundResource(imageId[i]);
imageViews.add(imageView);
}

for (int i = 0; i < imageId.length; i ++){
View view  = new View(this);
view.setBackgroundResource(R.drawable.guide_line_blue);
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(10,10);
view.setLayoutParams(layoutParams);
if (i > 0){
layoutParams.leftMargin = 10;

}
linearLayout.addView(view);
}
linearLayout.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
linearLayout.getViewTreeObserver().removeOnGlobalLayoutListener(this);
wid = linearLayout.getChildAt(1).getLeft() - linearLayout.getChildAt(0).getLeft();
Log.d("width", wid +"");
}
});

}

class MyViewPagerAdapter extends PagerAdapter {

@Override
public int getCount() {
return imageViews.size();
}

@Override
public boolean isViewFromObject(View view, Object object) {
return view==object;
}

@Override
public Object instantiateItem(ViewGroup container, int position) {
imageViews.get(position).setImageResource(imageId[position]);
container.addView(imageViews.get(position));
return imageViews.get(position);
}

@Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView((View)object);
}
}
}