按照字母查找手机文件

布局文件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/LinearLayout1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="请输入查找的内容" />

    <EditText
        android:id="@+id/edt"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" />

    <Button
        android:id="@+id/btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <TextView
        android:id="@+id/tv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:isScrollContainer="true" />

</LinearLayout>

package com.example.searchfile;

import java.io.File;

import android.os.Bundle;
import android.app.Activity;
import android.text.TextUtils;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends Activity {
    private EditText edt ;
    private TextView tv;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        edt = (EditText) findViewById(R.id.edt);
        tv = (TextView) findViewById(R.id.tv);
        findViewById(R.id.btn).setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                String key = edt.getText().toString().trim();
                if(TextUtils.isEmpty(key)){
                    tv.setText("输入的不能为空");
                }else{
                    tv.setText(searchFile(key));
                }

            }
        });
    }
    private String searchFile(String keyword){
        String msg = "";
        //获得根目录下的所有文件
        File[] file = new File("/").listFiles();
        //遍历此数组
        for (int i = 0; i < file.length; i++) {
            if(file[i].getName().indexOf(keyword)>=0){
                msg += file[i].getPath()+"\n";
            }
        }
        if(msg.equals("")){
            msg = "找不到此文件";
        }
        return msg;
    }

}