android原生的Spinner提供了下拉列表选项框,但在一些流行的APP中,原生的Spinner似乎不太受待见,而通常会有下图所示的下拉列表选项框:
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初始化状态:
点击弹出下拉选择选项框:
选中后:
注意那个指示箭头,如果把这个控件写的比较精细的话,在下拉-选择-复位过程中箭头是应该有动画旋转效果的。
这种样式的选择框实现方案很多,并且常见、常用,我自己写了一个,我写的这个例子的代码运行结果就是上图所示。
首先是MainActivity.Java:
package zhangphil.app; import android.content.Context; import android.graphics.Color; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.support.v7.widget.ListPopupWindow; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.AdapterView; import android.widget.ArrayAdapter; import android.widget.ImageView; import android.widget.LinearLayout; import android.widget.PopupWindow; import android.widget.TextView; import android.widget.Toast; public class MainActivity extends AppCompatActivity { private ListPopupWindow listPopupWindow = null; private ImageView arrowImageView; private TextView chooseText; private LinearLayout linearLayout; private SortAadapter adapter = null; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); linearLayout= (LinearLayout) findViewById(R.id.linearLayout); arrowImageView = (ImageView)findViewById(R.id.arrow); chooseText= (TextView) findViewById(R.id.chooseText); linearLayout.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { showListPopupWindow(linearLayout); } }); } private class SortAadapter extends ArrayAdapter { private String[] strs = {"最新", "推荐", "全部", "最热"}; private LayoutInflater inflater; private int res; public SortAadapter(Context context, int resource) { super(context, resource); inflater = LayoutInflater.from(context); res = resource; } @Override public View getView(int position, View convertView, ViewGroup parent) { if (convertView == null) convertView = inflater.inflate(res, null); TextView text = (TextView) convertView.findViewById(android.R.id.text1); text.setText(getItem(position)); text.setTextColor(Color.WHITE); text.setTextSize(10); convertView.setBackgroundColor(Color.RED); return convertView; } @Override public String getItem(int position) { return strs[position]; } @Override public int getCount() { return strs.length; } } public void showListPopupWindow(View view) { if (listPopupWindow == null) listPopupWindow = new ListPopupWindow(this); if (adapter == null) { adapter = new SortAadapter(this, android.R.layout.simple_list_item_1); // ListView适配器 listPopupWindow.setAdapter(adapter); // 选择item的监听事件 listPopupWindow.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int pos, long id) { Toast.makeText(getApplicationContext(), adapter.getItem(pos), Toast.LENGTH_SHORT).show(); chooseText.setText(adapter.getItem(pos)); listPopupWindow.dismiss(); } }); listPopupWindow.setOnDismissListener(new PopupWindow.OnDismissListener() { @Override public void onDismiss() { //旋转0度是复位ImageView arrowImageView.animate().setDuration(500).rotation(0).start(); } }); } // ListPopupWindow的锚,弹出框的位置是相对当前View的位置 listPopupWindow.setAnchorView(view); listPopupWindow.setVerticalOffset(dip2px(this,5)); // 对话框的宽高 listPopupWindow.setWidth(view.getWidth()); listPopupWindow.setModal(true); listPopupWindow.show(); arrowImageView.animate().setDuration(500).rotation(180).start(); } public static int dip2px(Context context, float dipValue) { float sDensity = context.getResources().getDisplayMetrics().density; final float scale = sDensity; return (int) (dipValue * scale + 0.5f); } }
布局文件:
<?xml version="1.0" encoding="utf-8"?>
LinearLayout的背景需要一个圆角背景res/drawable/round_corner_line_radius_3dp.xml:
<?xml version="1.0" encoding="UTF-8"?>
箭头icon.png:
附:Android第三方开源下拉框NiceSpinner
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