Android攻城獅學習筆記-進階篇一

public class MainActivity extends ActionBarActivity {
    
    private ListView listView;
    private ArrayAdapter<String>arrAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.listviewtest);
        
        listView = (ListView)findViewById(R.id.listView1);
        
        //1 新建一個適配器（3個參數爲：上下文，當前ListView加載的每個列表項對應的佈局文件，數據源）
        //2 適配器加載數據源
        String[] data = {"第一條item","第二條item","第三條item"};
        arrAdapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, data);
        
        //3 視圖加載適配器
        listView.setAdapter(arrAdapter);
    }

}

SimpleAdapter:實現效果

public class MainActivity extends ActionBarActivity {
    
    private ListView listView;
    private SimpleAdapter simpAdapter;
    private List<Map<String,Object>> dataList;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.listviewtest);
        
        listView = (ListView)findViewById(R.id.listView1);
        
        /*1 新建一個適配器（5個參數爲：
         *context:上下文
         *data:數據源 List<? extends Map<String, ?>> 一個Map所組成的list組合 
         *每個Map都會去對應ListView列表中的一行
         *每個Map（鍵值對）中的鍵必須包含全部在from中所指定的鍵
         *resource：列表項的佈局文件ID
         *from：Map中的鍵名
         *to：綁定數據視圖中的ID，與from成對應關係
         *2 適配器加載數據源
         * 
         * */
        dataList = new ArrayList<Map<String, Object>>();
        simpAdapter = new SimpleAdapter(this, getData(), R.layout.itemtest, new String[]{"img","text"}, new int[]{R.id.imageView1,R.id.textView1});
        
        //3 視圖加載適配器
        listView.setAdapter(simpAdapter);
    }
    
    private List<Map<String,Object>> getData(){
        
        for(int i = 0 ; i<20 ;i++){
            Map<String,Object> map = new HashMap<String,Object>();
            map.put("img", R.drawable.ic_launcher);
            map.put("text", "你好" + i);
            dataList.add(map);
        }
        return dataList;
    }

}

監聽器：是程序和用戶交互的橋樑

1）實現接口

2）設置監聽

3）重寫監聽方法

OnItemClickListener:能夠處理視圖中單個條目的點擊事件

public class MainActivity extends ActionBarActivity implements OnItemClickListener

listView.setOnItemClickListener(this);

@Override
    public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
        String text = listView.getItemAtPosition(arg2) + "";   //這裏有「」 不須要進行類型轉換 不然因爲listView.getItemAtPosition(arg2)返回的是object類型，須要進行類型轉換
        Toast.makeText(this, "position = " + arg2 + "text = " + text, Toast.LENGTH_LONG).show();        
    }

OnScrollListener:監測滾動的變化，能夠用於視圖在滾動中加載數據

public class MainActivity extends ActionBarActivity implements OnScrollListener

listView.setOnScrollListener(this);

@Override
    public void onScrollStateChanged(AbsListView view, int scrollState) {
        switch(scrollState){
        case SCROLL_STATE_FLING:
            Log.i("Main", "視圖正在滑動，可是手指已經離開了屏幕");
            Map<String, Object> map = new HashMap<String,Object>();
            map.put("img", R.drawable.ic_launcher);
            map.put("text", "新增項");
            dataList.add(map);  //數據集已經發生變化
            simpAdapter.notifyDataSetChanged(); //須要通知界面刷新
            break;
        case SCROLL_STATE_IDLE:
            Log.i("Main", "視圖沒有滑動");
            break;
        case SCROLL_STATE_TOUCH_SCROLL:
            Log.i("Main", "視圖正在滑動，手指還沒有離開屏幕");
            break;
        }       
    }

第3章使用DatePicker及TimePicker顯示當前日期和時間

public class MainActivity extends ActionBarActivity {
    
    private Calendar cal;  //自帶類，用於獲取年月日時分
    private int year;   //聲明年月日時分
    private int month;
    private int day;
    private int hour;
    private int minute;
    
    private DatePicker datePicker;   //聲明activity上的兩個控件
    private TimePicker timePicker;
    
    private Context mcontext;  //上下文變量
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        cal = Calendar.getInstance();  //得到日曆類實例
        year = cal.get(Calendar.YEAR);  //年月日時分初始值得到
        month = cal.get(Calendar.MONTH) + 1;
        day = cal.get(Calendar.DAY_OF_MONTH);
        hour = cal.get(Calendar.HOUR_OF_DAY);
        minute = cal.get(Calendar.MINUTE);
        mcontext = this;
        
        setTitle(year + "-" + month + "-" + day + " " + hour + ":" + minute);  //title欄初始顯示
        
        datePicker = (DatePicker)findViewById(R.id.datePicker1);   //獲取頁面按鈕
        timePicker = (TimePicker)findViewById(R.id.timePicker1);
        
        datePicker.init(year, cal.get(Calendar.MONTH), day, new OnDateChangedListener() {   //datePicker經過init()方法進行初始化，其中的OnDateChangedListener()用來監聽日期修改
            
            @Override
            public void onDateChanged(DatePicker arg0, int arg1, int arg2, int arg3) {
                
                setTitle(arg1 + "-" + (arg2 + 1) + "-" + arg3);  //日期修改後須要作什麼
                
            }
        });
        
        timePicker.setOnTimeChangedListener(new OnTimeChangedListener() {  //timePicker直接經過setOnTimeChangedListener()中的OnTimeChangedListener來監聽時間變化
            
            @Override
            public void onTimeChanged(TimePicker arg0, int arg1, int arg2) {
                
                setTitle(arg1 + ":" + arg2);  //時間修改後須要作什麼
                
            }
        });
        
        new DatePickerDialog(mcontext, new OnDateSetListener() {    //DatePickerDialog和TimePickerDialog 以彈出框的方式來修改
            
            @Override
            public void onDateSet(DatePicker arg0, int arg1, int arg2, int arg3) {
                setTitle(arg1 + "-" + (arg2 + 1) + "-" + arg3);   //回調方法，關閉彈框後須要作什麼
                
            }
        }, year, cal.get(Calendar.MONTH), day).show();  //經過.show()顯示出來
        
        new TimePickerDialog(mcontext, new OnTimeSetListener() {
            
            @Override
            public void onTimeSet(TimePicker arg0, int arg1, int arg2) {
                setTitle(arg1 + ":" + arg2);
                
            }
        }, hour, minute, true).show();
        
    }

}

第4章使用GridView以表格形式顯示多張照片

效果：

代碼：activity

public class MainActivity extends ActionBarActivity implements android.widget.AdapterView.OnItemClickListener{
    
    private GridView gridView;
    private List<Map<String,Object>> dataList;
    private int[] icon = {R.drawable.address_book,R.drawable.calendar,R.drawable.camera,R.drawable.clock,
            R.drawable.games_control,R.drawable.messenger,R.drawable.ringtone,R.drawable.settings,
            R.drawable.speech_balloon,R.drawable.weather,R.drawable.world,R.drawable.youtube};
    private String[] iconName = {"通信錄","日曆","照相機","鬧鐘","遊戲中心","信息","鈴聲","設置","語音","天氣","瀏覽器","視頻"};
    
    private SimpleAdapter simpleAdapter;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        gridView = (GridView)findViewById(R.id.gridView1);
        dataList = new ArrayList<Map<String,Object>>(); //數據源初始化
        simpleAdapter = new SimpleAdapter(this, getData(), R.layout.item, new String[]{"image","text"}, new int[]{R.id.image,R.id.text}); //定義適配器
        
        gridView.setAdapter(simpleAdapter);//加載適配器
        gridView.setOnItemClickListener(this);   //啓動監聽器
    
        
    }
    
    private List<Map<String,Object>> getData(){    //數據源獲取方法
        for(int i = 0; i < icon.length;i++){
            Map<String,Object> map = new HashMap<>();
            map.put("image", icon[i]);
            map.put("text", iconName[i]);
            dataList.add(map);
        }
        return dataList;
    }

    @Override
    public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {    //監聽到動做後 打印文字
        Toast.makeText(this, "我是" + iconName[arg2], Toast.LENGTH_SHORT).show();
        
    }

}

代碼:activity_main.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.gridviewtest.MainActivity"
    tools:ignore="MergeRootFrame" 
    android:background="#000000">   
    <!--android:background設置背景色爲黑色
      android:numColumns 設置每列有3個item
      android:verticalSpacing 設置item以前的垂直間距
      android:horizontalSpacing 設置item之間的水平間距-->

    <GridView
        android:id="@+id/gridView1"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:numColumns="3"   
        android:verticalSpacing="10dp"  
        android:horizontalSpacing="10dp">
    </GridView>

</FrameLayout>

代碼：item.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="vertical" 
    android:gravity="center">

    <ImageView
        android:id="@+id/image"
        android:layout_width="60dp"
        android:layout_height="60dp"
        android:src="@drawable/ic_launcher" />

    <TextView
        android:id="@+id/text"
        android:layout_margin="5dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textColor="#FFFFFF"
        android:text="Hi nihao"
        />

</LinearLayout>

第5章使用Spinner實現下拉列表

public class MainActivity extends ActionBarActivity implements OnItemSelectedListener {
    
    private TextView textView;
    private Spinner spinner;
    private List<String> list;
    private ArrayAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        textView = (TextView)findViewById(R.id.textView1);
        textView.setText("你選擇的是：北京");
        spinner = (Spinner)findViewById(R.id.spinner1);
        
        list = new ArrayList<String>();   //1 定義數據源
        list.add("北京");
        list.add("上海");
        list.add("廣州");
        list.add("深圳");
        
        adapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, list);  //2 定義適配器 加載數據源
        
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);  //3 爲適配器設置下拉時的樣式
        
        spinner.setAdapter(adapter);  //4 加載適配器 
        spinner.setOnItemSelectedListener(this);  // 5 啓動下拉選擇監聽
                
    }
    
    //定義監聽
    @Override
    public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,
            long arg3) {
        String cityName = (String) spinner.getItemAtPosition(arg2);
        textView.setText("你選擇的是：" + cityName);
        
    }

    @Override
    public void onNothingSelected(AdapterView<?> arg0) {
        // TODO Auto-generated method stub
        
    }
}

第6章使用ProgressBar實現進度條

大環形小環形水平進度有的能夠顯示刻度和百分比有的不顯示進度

關鍵屬性和方法：

第一顯示進度第二顯示進度最大顯示進度

demo效果：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.progressbar.MainActivity"
    tools:ignore="MergeRootFrame"
    android:orientation="vertical" >

    <ProgressBar
        android:id="@+id/progressBar1"
        style="?android:attr/progressBarStyleHorizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:max="100"
        android:progress="30"
        android:secondaryProgress="40" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/add"/>

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/reduce" />

    <Button
        android:id="@+id/button3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/reset" />

    <TextView
        android:id="@+id/textView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="TextView" />
    
</LinearLayout>

public class MainActivity extends ActionBarActivity implements OnClickListener{
    
    private ProgressBar progress;
    private Button btn_add;
    private Button btn_reduce;
    private Button btn_reset;
    private TextView textView;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        init();

    }

    private void init() {
        progress =(ProgressBar)findViewById(R.id.progressBar1);
        btn_add = (Button)findViewById(R.id.button1);
        btn_reduce = (Button)findViewById(R.id.button2);
        btn_reset = (Button)findViewById(R.id.button3);
        textView = (TextView)findViewById(R.id.textView1);
        
        int firstPro = progress.getProgress();
        int secPro = progress.getSecondaryProgress();
        int Max = progress.getMax();
        
        textView.setText("第一進度是：" + (int)(firstPro/(float)Max*100) + "%;" + "第二進度是：" + (int)(secPro/(float)Max*100) + "%;");
        btn_add.setOnClickListener(this);
        btn_reduce.setOnClickListener(this);
        btn_reset.setOnClickListener(this);
        
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
        //增長進度
        case R.id.button1:
            progress.incrementProgressBy(10);
            progress.incrementSecondaryProgressBy(10);
            break;
        //減小進度
        case R.id.button2:
            progress.incrementProgressBy(-10);
            progress.incrementSecondaryProgressBy(-10);
            break;
        //重置
        case R.id.button3:
            progress.setProgress(30);
            progress.setSecondaryProgress(40);
            break;
        }
        
        textView.setText("第一進度是：" + (int)(progress.getProgress()/(float)progress.getMax()*100) + "%;" + "第二進度是：" + (int)(progress.getSecondaryProgress()/(float)progress.getMax()*100) + "%;");
    }
}

關於progressDialog的內容未詳細看，關於自定義progressBar的內容未作筆記

第7章使用WebView顯示網頁

使用Intent意圖在咱們的應用中打開瀏覽器顯示網頁

public class MainActivity extends ActionBarActivity {
    
    private String url = "http://www.baidu.com";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        Uri uri = Uri.parse(url);
        Intent intent = new Intent(Intent.ACTION_VIEW, uri);
        startActivity(intent);
    }
}

能夠自定義webview，加載本地資源或web資源

定義webview：

public class MainActivity extends ActionBarActivity {
    
    private WebView webview;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        webview = (WebView)findViewById(R.id.webView1);
        //webview加載本地資源
//        webview.loadUrl("file:///android_asset/test.html");
        //webview加載web資源,必定要記得加上權限<uses-permission android:name="android.permission.INTERNET"/>
        webview.loadUrl("http://www.baidu.com");
        
    }
}

自定義webview默認使用系統瀏覽器或第三方瀏覽器打開網頁，能夠經過覆蓋這一行爲使得直接在webview中打開網頁

        webview.loadUrl("http://www.baidu.com");
        
        webview.getSettings().setJavaScriptEnabled(true); //有些頁面使用js，必須設置容許加載js才能打開
        
        webview.setWebViewClient(new WebViewClient(){
            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                view.loadUrl(url);
                //返回true則在webview中直接打開，返回false在系統或第三方瀏覽器中打開
                return true;
            }
        });

啓用支持javascript

webview = (WebView)findViewById(R.id.webView1);
WebSettings webSettings  = webview.getSettings();
webSettings.setJavaScriptEnabled(true);

後退與前進

//改寫物理按鍵——返回的邏輯
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            if (webview.canGoBack()) {
                webview.goBack();  //返回上一頁面
                return true;
            } else {
                System.exit(0);   //退出系統
            }
        } 
        return super.onKeyDown(keyCode, event);
    }