Java 按“后退”按钮时清除编辑文本的内容

我想清除editText的内容。当在键入时按下后退按钮时，它应该最小化键盘并将我带回起始列表视图…现在这样做时，它直接存在于应用程序中。。 一旦应用程序启动，键盘就会出现在屏幕上……相反，我希望它在用户单击编辑文本时出现

这是我的密码：

package com.example.acer.aartisangrah;

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

import java.util.ArrayList;

public class first extends AppCompatActivity {
EditText editText;
private ListView listView;

private String[] names = {"प्रार्थना", "सुखकर्ता दु:खहर्ता", "गजानना श्रीगणराया", "येई हो विठ्ठले", "लवथवती विक्राळा", "दुर्गे दुर्घट भारी", "आरती ज्ञानराजा",
        "हे भोळ्या शंकरा", "ओवाळू", "मंगेशा महारूद्रा", "आला गणराया", "शेंदुर लाल चढायो", "एकदंता", "कर्पूर गौरा", "हे गजवधना", "प्रथमेश्वरा", "जयदेवा हे  साईनाथा",
        "श्री सत्यनारायणाची आरती", "श्री महालक्ष्मीची आरती", "ॐ जय लक्ष्मी माता", "आरती संतोषी माता की", "धन्य धन्य हो प्रदक्षिणा", "सुखंकर्ता की दु:खहर्ता",
        "ॐ जय जगदीश", "हे गौरी गजानन", "घालीन लोटांगण"};
private int imageid[] = {R.drawable.ganeshaji, R.drawable.ganeshaji, R.drawable.ganeshaji, R.drawable.ganeshaji, R.drawable.ganeshaji, R.drawable.ganeshaji, R.drawable.ganeshaji, R.drawable.ganeshaji,
        R.drawable.ganeshaji, R.drawable.ganeshaji, R.drawable.ganeshaji, R.drawable.ganeshaji, R.drawable.ganeshaji, R.drawable.ganeshaji,
        R.drawable.ganeshaji, R.drawable.ganeshaji, R.drawable.ganeshaji, R.drawable.ganeshaji, R.drawable.ganeshaji, R.drawable.ganeshaji, R.drawable.ganeshaji,
        R.drawable.ganeshaji, R.drawable.ganeshaji, R.drawable.ganeshaji, R.drawable.ganeshaji, R.drawable.ganeshaji};
int textlength = 0;
ArrayList<String> text_sort = new ArrayList<String>();

ArrayList<Integer> image_sort = new ArrayList<Integer>();

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_first);
    listView = (ListView) findViewById(R.id.listView);
    editText = (EditText) findViewById(R.id.inputSearch);
    listView.setAdapter(new MyCustomAdapter(names, imageid));
    editText.addTextChangedListener(new TextWatcher()

    {
        public void afterTextChanged(Editable s) {
        }

        public void beforeTextChanged(CharSequence s, int start, int count, int after) {
        }

        public void onTextChanged(CharSequence s, int start, int before, int count) {
            textlength = editText.getText().length();
            text_sort.clear();
            image_sort.clear();
            for (int i = 0; i < names.length; i++) {
                if (textlength <= names[i].length()) {
                    if (editText.getText().toString().equalsIgnoreCase((String) names[i].subSequence(0, textlength))) {
                        text_sort.add(names[i]);
                        image_sort.add(imageid[i]);
                    }
                }
            }
            listView.setAdapter(new MyCustomAdapter(text_sort, image_sort));
        }

    });

    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

            TextView tv = (TextView) view.findViewById(R.id.textViewName);
            String strSelectedString = tv.getText().toString();
            for (int selectedPosition = 0; selectedPosition < names.length; selectedPosition++) {
                if (names[selectedPosition].equalsIgnoreCase(strSelectedString)) {
                    moveToNextActivity(selectedPosition);
                    break;
                }
            }

        }
    });
}


public void moveToNextActivity(int position) {
    if (position == 0) {
        Intent myIntent = new Intent(getApplicationContext(), akalp.class);
        startActivityForResult(myIntent, 0);
    }

    if (position == 1) {
        Intent myIntent = new Intent(getApplicationContext(), Sukharta.class);
        startActivityForResult(myIntent, 0);
    }

    if (position == 2) {
        Intent myIntent = new Intent(getApplicationContext(), gajananashriganraya.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 3) {
        Intent myIntent = new Intent(getApplicationContext(), yehihovittale.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 4) {
        Intent myIntent = new Intent(getApplicationContext(), lavathavthi.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 5) {
        Intent myIntent = new Intent(getApplicationContext(), durgedurgat.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 6) {
        Intent myIntent = new Intent(getApplicationContext(), nyanraja.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 7) {
        Intent myIntent = new Intent(getApplicationContext(), bolya.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 8) {
        Intent myIntent = new Intent(getApplicationContext(), vovalo.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 9) {
        Intent myIntent = new Intent(getApplicationContext(), mangesha.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 10) {
        Intent myIntent = new Intent(getApplicationContext(), alaganraya.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 11) {
        Intent myIntent = new Intent(getApplicationContext(), shendorlal.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 12) {
        Intent myIntent = new Intent(getApplicationContext(), ekdanta.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 13) {
        Intent myIntent = new Intent(getApplicationContext(), karpurgaura.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 14) {
        Intent myIntent = new Intent(getApplicationContext(), heygajavadana.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 15) {
        Intent myIntent = new Intent(getApplicationContext(), prathmeshvara.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 16) {
        Intent myIntent = new Intent(getApplicationContext(), sainatha.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 17) {
        Intent myIntent = new Intent(getApplicationContext(), satyanarayan.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 18) {
        Intent myIntent = new Intent(getApplicationContext(), jaidevijaidevi.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 19) {
        Intent myIntent = new Intent(getApplicationContext(), omjaimahalakshmi.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 20) {
        Intent myIntent = new Intent(getApplicationContext(), maitohaarti.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 21) {
        Intent myIntent = new Intent(getApplicationContext(), danyadanyaho.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 22) {
        Intent myIntent = new Intent(getApplicationContext(), sukhartakidukharta.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 23) {
        Intent myIntent = new Intent(getApplicationContext(), omjaijagdish.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 24) {
        Intent myIntent = new Intent(getApplicationContext(), heygaurigajanana.class);
        startActivityForResult(myIntent, 0);
    }
    if (position == 25) {
        Intent myIntent = new Intent(getApplicationContext(), ghalinlotangan.class);
        startActivityForResult(myIntent, 0);
    }
}

class MyCustomAdapter extends BaseAdapter {
    String[] data_text;
    int[] data_image;

    MyCustomAdapter() {

    }

    MyCustomAdapter(String[] names, int[] imageid) {
        data_text = names;
        data_image = imageid;
    }

    MyCustomAdapter(ArrayList<String> names, ArrayList<Integer> imageid) {
        data_text = new String[names.size()];
        data_image = new int[imageid.size()];
        for (int i = 0; i < names.size(); i++) {
            data_text[i] = names.get(i);
            data_image[i] = imageid.get(i);
        }
    }

    public int getCount() {
        return data_text.length;
    }

    public String getItem(int position) {
        return null;
    }

    public long getItemId(int position) {
        return position;
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        LayoutInflater inflater = getLayoutInflater();
        View row;
        row = inflater.inflate(R.layout.list_layout, parent, false);
        TextView textview = (TextView) row.findViewById(R.id.textViewName);
        ImageView imageview = (ImageView) row.findViewById(R.id.imageView);
        textview.setText(data_text[position]);
        imageview.setImageResource(data_image[position]);
        return (row);
    }
}
}

package com.example.acer.aartissangrah；
导入android.content.Intent；
导入android.os.Bundle；
导入android.support.v7.app.AppActivity；
导入android.text.Editable；
导入android.text.TextWatcher；
导入android.view.LayoutInflater；
导入android.view.view；
导入android.view.ViewGroup；
导入android.widget.AdapterView；
导入android.widget.BaseAdapter；
导入android.widget.EditText；
导入android.widget.ImageView；
导入android.widget.ListView；
导入android.widget.TextView；
导入java.util.ArrayList；
公共类首先扩展AppCompative活动{
编辑文本编辑文本；
私有列表视图列表视图；
私有字符串[]名称={”प्रार्थना", "सुखकर्ता दु:खहर्ता", "गजानना श्रीगणराया", "येई हो विठ्ठले", "लवथवती विक्राळा", "दुर्गे दुर्घट भारी", "आरती ज्ञानराजा",
"हे भोळ्या शंकरा", "ओवाळू", "मंगेशा महारूद्रा", "आला गणराया", "शेंदुर लाल चढायो", "एकदंता", "कर्पूर गौरा", "हे गजवधना", "प्रथमेश्वरा", "जयदेवा हे  साईनाथा",
"श्री सत्यनारायणाची आरती", "श्री महालक्ष्मीची आरती", "ॐ जय लक्ष्मी माता", "आरती संतोषी माता की", "धन्य धन्य हो प्रदक्षिणा", "सुखंकर्ता की दु:खहर्ता",
"ॐ जय जगदीश", "हे गौरी गजानन", "घालीन लोटांगण"};
private int-imageid[]={R.drawable.ganeshaji，R.drawable.ganeshaji，R.drawable.ganeshaji，R.drawable.ganeshaji，R.drawable.ganeshaji，R.drawable.ganeshaji，R.drawable.ganeshaji，R.drawable.ganeshaji，
R.drawable.ganeshaji，R.drawable.ganeshaji，R.drawable.ganeshaji，R.drawable.ganeshaji，R.drawable.ganeshaji，R.drawable.ganeshaji，
R.drawable.ganeshaji，R.drawable.ganeshaji，R.drawable.ganeshaji，R.drawable.ganeshaji，R.drawable.ganeshaji，R.drawable.ganeshaji，R.drawable.ganeshaji，
R.drawable.ganeshaji，R.drawable.ganeshaji，R.drawable.ganeshaji，R.drawable.ganeshaji，R.drawable.ganeshaji}；
int textlength=0；
ArrayList text_sort=新建ArrayList（）；
ArrayList image_sort=新建ArrayList（）；
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity_优先）；
listView=（listView）findViewById（R.id.listView）；
editText=（editText）findViewById（R.id.inputSearch）；
setAdapter（新的MyCustomAdapter（名称，imageid））；
editText.addTextChangedListener（新的TextWatcher（）
{
公共无效后文本已更改（可编辑）{
}
更改前文本之前的公共void（字符序列s、int start、int count、int after）{
}
public void onTextChanged（字符序列、int start、int before、int count）{
textlength=editText.getText（）.length（）；
text_sort.clear（）；
图像_sort.clear（）；
for（int i=0；i如果（textlength，则需要在activivty中重写onBackPressed（）方法，以便它不会完成

@Override
public void onBackPressed(){
    edittext.setText("");
    listView.setSelection(0);
    //or
    listView.smoothScrollToPosition(0);
}

上面的命令会将edittext设置为空字符串，然后在单击“上一步”按钮时将listview移回索引0


编辑

因此，如果您位于listview的顶部，为了仍然关闭应用程序，您需要添加一些逻辑来跟踪您在listview中的位置。最简单的方法是创建一个在listview滚动侦听器中更改的布尔值

public class first extends AppCompatActivity {
EditText editText;
private ListView listView;
boolean atTop; --> add this variable here. This will monitor our top status.
...// rest of logic

然后我们需要在onCreate中将scrollListener应用于listview

listView.setOnScrollListener(new AbsListView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(AbsListView absListView, int i) {

            }

            @Override
            public void onScroll(AbsListView absListView, int i, int i1, int i2) {
                if(i == 0){
                    View v = myListView.getChildAt(0);
                    int offset = (v == null) ? 0 : v.getTop();
                    if (offset == 0) {
                        atTop = true;
                        return;
                    }
                }else{
                    atTop = false;
                }
            }
});

在onscroll中，我们基本上是在检查我们是在顶部还是在其他地方。我们没有检查底部，因此这几乎可以在任何地方工作。然后在onBackPressed中，您应该执行以下操作：

@Override
public void onBackPressed(){
     if(atTop){
          super.onBackPressed();
     }else {
          edittext.setText("");
          listView.setSelection(0);
          //or
          listView.smoothScrollToPosition(0);
      }
}

因此，现在如果我们在顶部，我们希望onBackPressed与正常运行时一样运行。如果我们没有清除编辑文本并滚动到顶部。
现在的问题是在返回主列表视图后，按back按钮应关闭应用程序……上述解决方案解决了editText clear问题……如果editText为e，它也应关闭吗mpty或如果您在列表视图的索引0处？我应该仅在索引0处关闭…如果用户正在键入并希望返回索引0…单击“上一步”按钮应清除编辑文本的内容并返回索引0