Android ListView头部随着上下拖动缩放

最新推荐文章于 2018-03-30 13:58:00 发布

android-李志强

最新推荐文章于 2018-03-30 13:58:00 发布

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本文链接：https://blog.youkuaiyun.com/lzq520210/article/details/50515634

本文介绍了在Android应用开发中如何通过创建两个活动类（FixedActivity 和 ScaleActivity）来实现按钮点击时跳转到不同活动并展示列表视图的固定与缩放效果。通过代码实现，展示了如何使用ListView和LinearLayout进行布局，并通过自定义适配器和监听器来控制列表视图的头部可见性和缩放行为。

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效果图如下：

代码如下：

MainActivity：

public class MainActivity extends Activity {

   private Button btn_fixed;
   private Button btn_scale;
   
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      requestWindowFeature(Window.FEATURE_NO_TITLE);
      setContentView(R.layout.activity_main);
      
      btn_fixed = (Button) findViewById(R.id.btn_one);
      btn_scale = (Button) findViewById(R.id.btn_two);
      
      btn_fixed.setOnClickListener(new OnClickListener() {
         
         @Override
         public void onClick(View v) {
            Intent fixIntent = new Intent(MainActivity.this,FixedActivity.class);
            startActivity(fixIntent);
         }
      });
      btn_scale.setOnClickListener(new OnClickListener() {
         
         @Override
         public void onClick(View v) {
            Intent fixIntent = new Intent(MainActivity.this,ScaleActivity.class);
            startActivity(fixIntent);
         }
      });
   }

}

FixedActivity代码：
public class FixedActivity extends Activity implements OnScrollListener{
   
   private ListView lv_test;
   private LinearLayout ll_tt;
   private TextView tv_shadow;

   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      requestWindowFeature(Window.FEATURE_NO_TITLE);
      setContentView(R.layout.activity_lv);
      lv_test = (ListView) findViewById(R.id.lv_test);
      tv_shadow = (TextView) findViewById(R.id.tv_shadow);
      
      View view = LayoutInflater.from(this).inflate(R.layout.lv_test, null);
      View view2 = LayoutInflater.from(this).inflate(R.layout.item, null);
      ll_tt = (LinearLayout) view2.findViewById(R.id.ll_tt);
      
      lv_test.addHeaderView(view);
      lv_test.addHeaderView(view2);
      lv_test.setOnScrollListener(this);
      lv_test.setAdapter(new MyAdapter());
   }
   
   class MyAdapter extends BaseAdapter{

      @Override
      public int getCount() {
         return 40;
      }

      @Override
      public Object getItem(int position) {
         return position;
      }

      @Override
      public long getItemId(int position) {
         return 0;
      }

      @Override
      public View getView(int position, View convertView, ViewGroup parent) {
         TextView tv = new TextView(FixedActivity.this);
         tv.setText("listview"+position);
         return tv;
      }
      
   }

   @Override
   public void onScrollStateChanged(AbsListView view, int scrollState) {
   }

   @SuppressLint("NewApi")
   @Override
   public void onScroll(AbsListView view, int firstVisibleItem,
         int visibleItemCount, int totalItemCount) {
      int top2 = ll_tt.getTop();
      if (top2 <= 0 || firstVisibleItem >= 1 ) {
         tv_shadow.setVisibility(View.VISIBLE);
      }else {
         tv_shadow.setVisibility(View.INVISIBLE);
      }
   }
}
ScaleActivity代码如下：
public class ScaleActivity extends Activity implements OnScrollListener{

   private ListView lv_test;
   private LinearLayout ll_tt;
   private TextView tv;
   private int top;
   private float scale = 1;
   
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      
      requestWindowFeature(Window.FEATURE_NO_TITLE);
      setContentView(R.layout.activity_lv);
      lv_test = (ListView) findViewById(R.id.lv_test);
      
      View view = LayoutInflater.from(this).inflate(R.layout.lv_test, null);
      View view2 = LayoutInflater.from(this).inflate(R.layout.item, null);
      ll_tt = (LinearLayout) view2.findViewById(R.id.ll_tt);
      tv = (TextView) view2.findViewById(R.id.tv_tt);
      
      lv_test.addHeaderView(view);
      lv_test.addHeaderView(view2);
      lv_test.setOnScrollListener(this);
      lv_test.setAdapter(new MyAdapter());
   }
   
   @Override
   protected void onResume() {
      super.onResume();
      ViewTreeObserver vto = ll_tt.getViewTreeObserver();
      vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
         @Override
         public void onGlobalLayout() {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
               ll_tt.getViewTreeObserver().removeOnGlobalLayoutListener(this);
            }
            top = ll_tt.getTop();
            scale = (float) scale / (float) top;
            System.out.println("scale : " + scale);
         }
      });
   }
   
   class MyAdapter extends BaseAdapter{

      @Override
      public int getCount() {
         return 40;
      }

      @Override
      public Object getItem(int position) {
         return position;
      }

      @Override
      public long getItemId(int position) {
         return 0;
      }

      @Override
      public View getView(int position, View convertView, ViewGroup parent) {
         TextView tv = new TextView(ScaleActivity.this);
         tv.setText("listview"+position);
         return tv;
      }
      
   }

   @Override
   public void onScrollStateChanged(AbsListView view, int scrollState) {
   }

   @Override
   public void onScroll(AbsListView view, int firstVisibleItem,
         int visibleItemCount, int totalItemCount) {
      int top2 = ll_tt.getTop();
      if (top2 >= 0) {
         tv.setScaleX(top2 * scale);
         tv.setScaleY(top2 * scale);
      }
   }
}
activity_main代码如下：

<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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <Button
        android:id="@+id/btn_one"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="title固定"  />
    <Button
        android:id="@+id/btn_two"
        android:layout_below="@id/btn_one"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="title缩放"  />

</RelativeLayout>
 activity_lv代码如下：
<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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:background="#ffffffff"
    tools:context=".MainActivity" >

    <ListView 
        android:id="@+id/lv_test"
        android:background="#ffffffff"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:divider="@null"
        android:dividerHeight="0dp"
        android:scrollbars="none"  />

    <TextView 
        android:id="@+id/tv_shadow"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:textSize="30sp"
        android:text="这是测试条目"
        android:background="#ffffffff"
        android:visibility="invisible"
        android:gravity="center"/>
</RelativeLayout>

lv_text代码如下：
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#ffffffff"
    android:id="@+id/ll"
    android:orientation="vertical" >
    
    <ImageView 
        android:id="@+id/iv"
        android:layout_width="wrap_content"
        android:layout_height="200dp"
        android:background="@mipmap/widget_autoscroollview_demo_banner1" />
</LinearLayout>
item代码如下：
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/ll_tt"
    android:orientation="vertical" >
    
   <TextView 
        android:id="@+id/tv_tt"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:textSize="30sp"
        android:text="这是测试条目"
        android:visibility="visible"
        android:gravity="center"/>
</LinearLayout>