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图片切换App实现细节整理与优化

本次介绍的图片切换App实现了两种切换效果：普通效果和特效切换。不同效果适用于不同的需求，分别展示对应的代码实现及其布局结构。

代码布局描述

主要XML代码（ActivityMain）的代码布局如下：

功能介绍与代码解读

主Activity代码实现：

public class MainActivity extends AppCompatActivity implements View.OnClickListener, ViewSwitcher.ViewFactory {    private ImageSwitcher is_1;    private Button btn_next;    private Button btn_previous;    private Button btn_3;    private int image[] = {        R.drawable.tian1, R.drawable.tian2, R.drawable.tian3, R.drawable.tian4    };    private int imageIndex = 0;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        is_1 = (ImageSwitcher) findViewById(R.id.is_1);        btn_next = (Button) findViewById(R.id.btn_next);        btn_previous = (Button) findViewById(R.id.btn_previous);        btn_3 = (Button) findViewById(R.id.btn_3);        btn_previous.setOnClickListener(this);        btn_next.setOnClickListener(this);        btn_3.setOnClickListener(this);        init();    }    @Override    public void onClick(View view) {        int id = view.getId();        if (id == R.id.btn_next) {            imageIndex = (imageIndex + 1) % image.length;            is_1.setInAnimation(this, R.anim.left_in);            is_1.setOutAnimation(this, R.anim.right_out);            is_1.setImageResource(image[imageIndex]);        } else if (id == R.id.btn_previous) {            imageIndex = (imageIndex - 1 + image.length) % image.length;            is_1.setInAnimation(this, R.anim.right_in);            is_1.setOutAnimation(this, R.anim.left_out);            is_1.setImageResource(image[imageIndex]);        } else if (id == R.id.btn_3) {            Intent intent = new Intent();            intent.setClass(this, other2.class);            startActivity(intent);        }    }    @Override    public View makeView() {        ImageView imageView = new ImageView(this);        return imageView;    }    private void init() {        is_1.setFactory(this);        is_1.setImageResource(image[imageIndex]);    }}

ViewPager适配器实现：

public class ViewPagerAdapter extends PagerAdapter {    private ArrayList
   
     views;    public ViewPagerAdapter(ArrayList
    
      views) {        this.views = views;    }    @Override    public int getCount() {        return views.size();    }    @Override    public Object instantiateItem(View view, int position) {        ((ViewPager) view).addView(views.get(position), 0);        return views.get(position);    }    @Override    public boolean isViewFromObject(View view, Object arg1) {        return (view == arg1);    }    @Override    public void destroyItem(View view, int position, Object arg2) {        ((ViewPager) view).removeView(views.get(position));    }}
    
   

另一种效果展示布局

other2布局文件：

其他特效实现代码：

public class other2 extends AppCompatActivity implements View.OnClickListener, ViewPager.OnPageChangeListener {    private ViewPager viewPager;    private ViewPagerAdapter vpAdapter;    private ArrayList
   
     views;    private int currentIndex;    private static final int[] pics = {R.drawable.one, R.drawable.two, R.drawable.three, R.drawable.four};    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_other2);        viewPager = (ViewPager) findViewById(R.id.viewpager);        vpAdapter = new ViewPagerAdapter(new ArrayList
    
     ());        viewPager.setAdapter(vpAdapter);        for (int i = 0; i < pics.length; i++) {            ImageView iv = new ImageView(this);            LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.FILL_PARENT);            iv.setLayoutParams(params);            iv.setImageResource(pics[i]);            iv.setTag(i);            views.add(iv);            vpAdapter.views.add(iv);        }        viewPager.setOnPageChangeListener(this);        currentIndex = 0;    }    @Override    public void onClick(View view) {        int position = (Integer) view.getTag();        if (position != currentIndex) {            viewPager.setCurrentItem(position);            currentIndex = position;            updateDot(position);        }    }    private void updateDot(int position) {        for (int i = 0; i < views.size(); i++) {            if (i != position) {                views.get(i).setImageResource(R.drawable.default_point);            } else {                views.get(i).setImageResource(R.drawable.active_point);            }        }    }}
    
   

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