底部弹出PopupWindow+地址三级联动，多问题全面分析，详细注释

<span style="font-size:18px;">public class PopHelper {
    private Context mContext;
    private PopupWindow pw;
    private CityPicker cityPicker;
    public PopHelper(Context context) {
        mContext = context;
    }
    /**
     * @param view
     * @param itemsOnClick 抛出一个OnClickListener接口
     */
    public void showAddressPop(View view, final Activity activity, View.OnClickListener itemsOnClick) {
        // 设置pw里的点击事件
        LinearLayout addressView = (LinearLayout) View.inflate(mContext, R.layout.pop_address, null);
        Button btnPopAddressCencel = (Button) addressView.findViewById(R.id.btn_pop_address_cencel);
        btnPopAddressCencel.setOnClickListener(itemsOnClick);
        Button btnPopAddressEnter = (Button) addressView.findViewById(R.id.btn_pop_address_enter);
        btnPopAddressEnter.setOnClickListener(itemsOnClick);
        cityPicker = (CityPicker) addressView.findViewById(R.id.citypicker);
        //-2是包裹自己，-1是填充父容器
        pw = new PopupWindow(addressView, -1, -2);
        //先关闭
        colsePopupwindow();
        //必须要设置一个背景
        pw.setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
        //点击外边可关闭pw
        pw.setOutsideTouchable(true);
        //pw内可获取焦点
        pw.setFocusable(true);
        // 设置背景颜色变暗
        WindowManager.LayoutParams lp = activity.getWindow().getAttributes();
        lp.alpha = 0.7f;
        activity.getWindow().setAttributes(lp);
        //退出时恢复透明度
        pw.setOnDismissListener(new PopupWindow.OnDismissListener() {
            @Override
            public void onDismiss() {
                WindowManager.LayoutParams lp = activity.getWindow().getAttributes();
                lp.alpha = 1f;
                activity.getWindow().setAttributes(lp);
            }
        });
        //设置动画
        pw.setAnimationStyle(R.style.take_photo_anim);
        //显示。y轴距离底部100是因为部分手机有虚拟按键，所以实际项目中要动态设置
        pw.showAtLocation(view, Gravity.BOTTOM, 0, 100);
    }
    /**
     *
     * @return 获取控件中的地址数据
     */
    public String getAddressData() {
        String cData = cityPicker.getCity_string();
        return cData;
    }
    /**
     * 关闭pw
     */
    public void colsePopupwindow() {
        if (pw != null && pw.isShowing()) {
            pw.dismiss();
            pw = null;
        }
    }
}</span>

pop_enter_anim.xml
<span style="font-size:18px;"><?xml version="1.0" encoding="utf-8"?> 
<set xmlns:android="http://schemas.android.com/apk/res/android"> 
  <translate 
    android:duration="200" 
    android:fromYDelta="100%p" 
    android:toYDelta="0" /> 
  <alpha 
    android:duration="200" 
    android:fromAlpha="0.0" 
    android:toAlpha="1.0" /> 
</set></span>
pop_exit_anim.xml
<span style="font-size:18px;"><?xml version="1.0" encoding="utf-8"?> 
<set xmlns:android="http://schemas.android.com/apk/res/android"> 
  <translate 
    android:duration="200" 
    android:fromYDelta="0" 
    android:toYDelta="50%p" /> 
  <alpha 
    android:duration="200" 
    android:fromAlpha="1.0" 
    android:toAlpha="0.0" /> 
</set> </span>

<span style="font-size:18px;">public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private TextView textView1, textView2;
    private Button button1, button2;
    private PopHelper popHelper;//pop
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView1 = (TextView) findViewById(R.id.textView1);
        textView2 = (TextView) findViewById(R.id.textView2);
        button1 = (Button) findViewById(R.id.button1);
        button1.setOnClickListener(this);
        button2 = (Button) findViewById(R.id.button2);
        button2.setOnClickListener(this);
    }
    /**
     * 实现popHelper中的item接口
     */
    private View.OnClickListener onClickListener = new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            switch (v.getId()) {
                case R.id.btn_pop_address_cencel:
                    popHelper.colsePopupwindow();
                    break;
                case R.id.btn_pop_address_enter:
                    String addressData = popHelper.getAddressData();
                    if (flag) {
                        textView1.setText(addressData);
                    } else {
                        textView2.setText(addressData);
                    }
                    popHelper.colsePopupwindow();
                    break;
            }
        }
    };
    boolean flag;//用于pop标记显示,避免多个地方显示却只填充一个textview的情况
    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.button1:
                popHelper = new PopHelper(getApplicationContext());
                popHelper.showAddressPop(v, MainActivity.this, onClickListener);
                flag = true;
                break;
            case R.id.button2:
                popHelper = new PopHelper(getApplicationContext());
                popHelper.showAddressPop(v, MainActivity.this, onClickListener);
                flag = false;
                break;
        }
    }
}</span>

<span style="font-size:18px;">compile 'com.google.code.gson:gson:2.6.2'</span>