第一行代码Android学习（三）

第一行代码Android学习：第三部分主要涉及到简单的自定义控件和优化后ListView的写法

• 1.activity_main.xml

<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"
    tools:context=".MainActivity" >

    <com.example.dyhdm_02_00uicustomviews.TitleLayout
        android:id="@+id/tl_title"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
    </com.example.dyhdm_02_00uicustomviews.TitleLayout>

    <ListView
        android:id="@+id/lv_test"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_below="@id/tl_title" >
    </ListView>

</RelativeLayout>

• 2.item_test.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal" >

    <TextView
        android:id="@+id/tv1"
        android:layout_marginRight="50dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
    <TextView
        android:id="@+id/tv2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>

• 3.title.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal" >

    <Button
        android:id="@+id/bt_back"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="返回" >
    </Button>

    <TextView
        android:id="@+id/tv_title"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:gravity="center"
        android:textSize="20dp"
        android:text="标题" />
    <Button
        android:id="@+id/bt_edit"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="编辑" >
    </Button>
</LinearLayout>

• 4.MainActivity.java

package com.example.dyhdm_02_00uicustomviews;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;
import android.widget.Toast;

public class MainActivity extends Activity {

    private ListView lv_test;
    private TestAdapter adapter;
    private List<Map<String, String>> list = new ArrayList<Map<String, String>>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_main);
        for (int i = 0; i < 5; i++) {
            Map<String, String> map = new HashMap<String, String>();
            map.put("arg1", "111");
            map.put("arg2", "222");
            list.add(map);
        }

        lv_test = (ListView) findViewById(R.id.lv_test);
        adapter = new TestAdapter(this, R.layout.item_test, list);
        lv_test.setAdapter(adapter);
        lv_test.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                Toast.makeText(MainActivity.this, position+"", Toast.LENGTH_SHORT).show();
            }

        });
    }

}

• 5.TestAdapter.java

/*
 * @Title:  TestAdapter.java
 * @Description:  TODO 
 * @author:  张志安
 * @data:  2016-8-15 下午2:00:49
 * 
 */
package com.example.dyhdm_02_00uicustomviews;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import android.content.Context;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

/** 
 * TODO 测试用的Adapter
 * 
 * @author 张志安
 * @date: 2016-8-15 下午2:00:49
 */
public class TestAdapter extends ArrayAdapter {

    private int resourceId;
    private List<Map<String, String>> list = new ArrayList<Map<String, String>>();

    /**
     * <默认构造函数>
     */
    public TestAdapter(Context context, int textViewResourceId, List objects) {
        super(context, textViewResourceId, objects);
        resourceId = textViewResourceId;
        list = objects;
    }

    /**
     * 重载方法
     */
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View view;
        ViewHold viewHold;
        if (convertView == null) {
            view = LayoutInflater.from(getContext()).inflate(resourceId, null);
            viewHold = new ViewHold();
            viewHold.tv1 = (TextView) view.findViewById(R.id.tv1);
            viewHold.tv2 = (TextView) view.findViewById(R.id.tv2);
            view.setTag(viewHold);
        } else {
            view = convertView;
            viewHold = (ViewHold) view.getTag();
        }
        viewHold.tv1.setText(list.get(position).get("arg1"));
        viewHold.tv2.setText(list.get(position).get("arg2"));
        return view;
    }

    class ViewHold {
        TextView tv1;
        TextView tv2;
    }
}

• 6.TitleLayout.java

/*
 * @Title:  TitleLayout.java
 * @Description:  TODO 
 * @author:  张志安
 * @data:  2016-8-15 上午10:48:00
 * 
 */
package com.example.dyhdm_02_00uicustomviews;

import android.app.Activity;
import android.content.Context;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.Toast;

/**
 * TODO 自定义的控件
 * @author  张志安
 * @data:  2016-8-15 上午10:48:00
 */
public class TitleLayout extends LinearLayout {

    /** 
     * <默认构造函数>
     */
    public TitleLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
        LayoutInflater.from(context).inflate(R.layout.title, this);
        Button bt_back = (Button) findViewById(R.id.bt_back);
        Button bt_edit = (Button) findViewById(R.id.bt_edit);
        bt_back.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                ((Activity) getContext()).finish();
            }
        });
        bt_edit.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                Toast.makeText(getContext(), "Edit", Toast.LENGTH_SHORT).show();
            }
        });
    }

}

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