Android中的LayoutInflater有什麼做用？

時間 2020-04-17

標籤 android layoutinflater 什麼欄目 Android 简体版

原文原文鏈接

Android中的LayoutInflater什麼用？ java

#1樓

這是另外一個與前一個相似的示例，但進一步展現了它能夠提供的膨脹參數和動態行爲。 android

假設您的ListView行佈局能夠包含可變數量的TextView。因此首先你膨脹基礎項View（就像前面的例子同樣），而後在運行時循環動態添加TextViews。使用android：layout_weight還能夠完美地對齊全部內容。 ide

如下是Layouts資源：佈局

list_layout.xml this

<?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="wrap_content" 
    android:orientation="horizontal" >
    <TextView 
        android:id="@+id/field1"
        android:layout_width="0dp"  
        android:layout_height="wrap_content" 
        android:layout_weight="2"/>
    <TextView 
        android:id="@+id/field2"
        android:layout_width="0dp"  
        android:layout_height="wrap_content" 
        android:layout_weight="1"
/>
</LinearLayout>

schedule_layout.xml spa

<?xml version="1.0" encoding="utf-8"?>
   <TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="0dp"  
    android:layout_height="wrap_content" 
    android:layout_weight="1"/>

在BaseAdapter類的擴展中覆蓋getView方法 code

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    LayoutInflater inflater = activity.getLayoutInflater();
    View lst_item_view = inflater.inflate(R.layout.list_layout, null);
    TextView t1 = (TextView) lst_item_view.findViewById(R.id.field1);
    TextView t2 = (TextView) lst_item_view.findViewById(R.id.field2);
    t1.setText("some value");
    t2.setText("another value");

    // dinamically add TextViews for each item in ArrayList list_schedule
    for(int i = 0; i < list_schedule.size(); i++){
        View schedule_view = inflater.inflate(R.layout.schedule_layout, (ViewGroup) lst_item_view, false);
        ((TextView)schedule_view).setText(list_schedule.get(i));
        ((ViewGroup) lst_item_view).addView(schedule_view);
    }
    return lst_item_view;
}

注意不一樣的inflate方法調用： xml

inflater.inflate(R.layout.list_layout, null); // no parent
inflater.inflate(R.layout.schedule_layout, (ViewGroup) lst_item_view, false); // with parent preserving LayoutParams

#2樓

這裏是一個示例，用於爲佈局的根視圖建立一個引用，對其進行膨脹並將其與setContentView（View視圖）一塊兒使用對象

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    LayoutInflater li=getLayoutInflater();
    View rootView=li.inflate(R.layout.activity_main,null);
    setContentView(rootView);


}

#3樓

LayoutInflater.inflate（）提供了一種方法，用於將定義視圖的res / layout / * .xml文件轉換爲可在應用程序源代碼中使用的實際View對象。 ip

基本的兩個步驟：獲取inflater而後膨脹資源

你怎麼獲得inflater？

LayoutInflater inflater = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

假設xml文件是「list_item.xml」，你如何獲得視圖？

View view = inflater.inflate(R.layout.list_item, parent, false);

#4樓

膨脹意味着讀取描述佈局（或GUI元素）的XML文件並建立與其對應的實際對象，從而使對象在Android應用程序中可見。

final Dialog mDateTimeDialog = new Dialog(MainActivity.this);

// Inflate the root layout
final RelativeLayout mDateTimeDialogView = (RelativeLayout) getLayoutInflater().inflate(R.layout.date_time_dialog, null);

// Grab widget instance
final DateTimePicker mDateTimePicker = (DateTimePicker) mDateTimeDialogView.findViewById(R.id.DateTimePicker);

該文件能夠保存爲date_time_dialog.xml ：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/DateTimeDialog" android:layout_width="100px"
    android:layout_height="wrap_content">
    <com.dt.datetimepicker.DateTimePicker
            android:id="@+id/DateTimePicker" android:layout_width="fill_parent"
            android:layout_height="wrap_content" />
    <LinearLayout android:id="@+id/ControlButtons"
            android:layout_width="fill_parent" android:layout_height="wrap_content"
            android:layout_below="@+id/DateTimePicker"
            android:padding="5dip">
            <Button android:id="@+id/SetDateTime" android:layout_width="0dip"
                    android:text="@android:string/ok" android:layout_weight="1"
                    android:layout_height="wrap_content"
                   />
            <Button android:id="@+id/ResetDateTime" android:layout_width="0dip"
                    android:text="Reset" android:layout_weight="1"
                    android:layout_height="wrap_content"
                    />
            <Button android:id="@+id/CancelDialog" android:layout_width="0dip"
                    android:text="@android:string/cancel" android:layout_weight="1"
                    android:layout_height="wrap_content"
                     />
    </LinearLayout>

此文件能夠保存爲date_time_picker.xml ：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent" android:layout_height="wrap_content" `enter code here`
    android:padding="5dip" android:id="@+id/DateTimePicker">
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:baselineAligned="true"
android:orientation="horizontal">

    <LinearLayout
    android:id="@+id/month_container"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginLeft="1dp"
    android:layout_marginTop="5dp"
    android:layout_marginRight="5dp"
    android:layout_marginBottom="5dp"
    android:gravity="center"
    android:orientation="vertical">
    <Button
        android:id="@+id/month_plus"
        android:layout_width="45dp"
        android:layout_height="45dp"  
        android:background="@drawable/image_button_up_final"/>
    <EditText
        android:id="@+id/month_display"
        android:layout_width="45dp"
        android:layout_height="35dp"
        android:background="@drawable/picker_middle"
        android:focusable="false"
        android:gravity="center"
        android:singleLine="true"
        android:textColor="#000000">
    </EditText>
    <Button
        android:id="@+id/month_minus"
        android:layout_width="45dp"
        android:layout_height="45dp"       
        android:background="@drawable/image_button_down_final"/>
</LinearLayout>
<LinearLayout
    android:id="@+id/date_container"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginLeft="0.5dp"
    android:layout_marginTop="5dp"
    android:layout_marginRight="5dp"
    android:layout_marginBottom="5dp"
    android:gravity="center"
    android:orientation="vertical">
    <Button
        android:id="@+id/date_plus"
        android:layout_width="45dp"
        android:layout_height="45dp"       
        android:background="@drawable/image_button_up_final"/>
    <EditText
        android:id="@+id/date_display"
        android:layout_width="45dp"
        android:layout_height="35dp"
        android:background="@drawable/picker_middle"
        android:gravity="center"
        android:focusable="false"
        android:inputType="number"
        android:textColor="#000000"
        android:singleLine="true"/>
    <Button
        android:id="@+id/date_minus"
        android:layout_width="45dp"
        android:layout_height="45dp"      
        android:background="@drawable/image_button_down_final"/>
</LinearLayout>
<LinearLayout
    android:id="@+id/year_container"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginLeft="0.5dp"
    android:layout_marginTop="5dp"
    android:layout_marginRight="5dp"
    android:layout_marginBottom="5dp"
    android:gravity="center"
    android:orientation="vertical">
    <Button
        android:id="@+id/year_plus"
        android:layout_width="45dp"
        android:layout_height="45dp"       
            android:background="@drawable/image_button_up_final"/>
    <EditText
        android:id="@+id/year_display"
        android:layout_width="45dp"
        android:layout_height="35dp"
        android:background="@drawable/picker_middle"
        android:gravity="center"
        android:focusable="false"
        android:inputType="number"
        android:textColor="#000000"
        android:singleLine="true"/>
    <Button
        android:id="@+id/year_minus"
        android:layout_width="45dp"
        android:layout_height="45dp"       
        android:background="@drawable/image_button_down_final"/>
</LinearLayout>
<LinearLayout
        android:id="@+id/hour_container"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:layout_marginTop="5dp"
        android:layout_marginBottom="5dp"
        android:gravity="center"
        android:orientation="vertical">
        <Button
            android:id="@+id/hour_plus"
            android:layout_width="45dp"
            android:layout_height="45dp"          
            android:background="@drawable/image_button_up_final"/>
        <EditText
            android:id="@+id/hour_display"
            android:layout_width="45dp"
            android:layout_height="35dp"
            android:background="@drawable/picker_middle"
            android:gravity="center"
            android:focusable="false"
            android:inputType="number"
            android:textColor="#000000"
            android:singleLine="true">
        </EditText>
        <Button
            android:id="@+id/hour_minus"
            android:layout_width="45dp"
            android:layout_height="45dp"       
            android:background="@drawable/image_button_down_final"/>
    </LinearLayout>
    <LinearLayout
        android:id="@+id/min_container"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="0.35dp"
        android:layout_marginTop="5dp"
        android:layout_marginRight="5dp"
        android:layout_marginBottom="5dp"
        android:gravity="center"
        android:orientation="vertical">
        <Button
            android:id="@+id/min_plus"
            android:layout_width="45dp"
            android:layout_height="45dp"       
            android:background="@drawable/image_button_up_final"/>
        <EditText
            android:id="@+id/min_display"
            android:layout_width="45dp"
            android:layout_height="35dp"
            android:background="@drawable/picker_middle"
            android:gravity="center"
            android:focusable="false"
            android:inputType="number"
            android:textColor="#000000"
            android:singleLine="true"/>
        <Button
            android:id="@+id/min_minus"
            android:layout_width="45dp"
            android:layout_height="45dp"       
            android:background="@drawable/image_button_down_final"/>
    </LinearLayout>

    <LinearLayout 
        android:id="@+id/meridiem_container"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="0.35dp"
        android:layout_marginTop="5dp"
        android:layout_marginRight="5dp"
        android:layout_marginBottom="5dp"
        android:gravity="center"
        android:orientation="vertical">
        <ToggleButton 
            android:id="@+id/toggle_display"
            style="@style/SpecialToggleButton"
            android:layout_width="40dp"
            android:layout_height="32dp"
            android:layout_marginLeft="5dp"
            android:layout_marginTop="45dp"
            android:layout_marginRight="5dp"
            android:layout_marginBottom="5dp"
            android:padding="5dp"
            android:gravity="center"
            android:textOn="@string/meridiem_AM"
            android:textOff="@string/meridiem_PM"
            android:checked="true"/>

           <!--  android:checked="true" --> 

    </LinearLayout>
</LinearLayout>
</RelativeLayout>

MainActivity類保存爲MainActivity.java ：

public class MainActivity extends Activity {
    EditText editText;
    Button button_click;
    public static Activity me = null;
    String meridiem;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        editText = (EditText)findViewById(R.id.edittext1);
        button_click = (Button)findViewById(R.id.button1);
        button_click.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View view){
                final Dialog mDateTimeDialog = new Dialog(MainActivity.this);
                final RelativeLayout mDateTimeDialogView = (RelativeLayout)   getLayoutInflater().inflate(R.layout.date_time_dialog, null);
                final DateTimePicker mDateTimePicker = (DateTimePicker) mDateTimeDialogView.findViewById(R.id.DateTimePicker);
                // mDateTimePicker.setDateChangedListener();
                ((Button) mDateTimeDialogView.findViewById(R.id.SetDateTime)).setOnClickListener(new OnClickListener() {
                    public void onClick(View v) {
                        mDateTimePicker.clearFocus();
                        int hour = mDateTimePicker.getHour();
                        String result_string = mDateTimePicker.getMonth() +" "+   String.valueOf(mDateTimePicker.getDay()) + ", " + String.valueOf(mDateTimePicker.getYear())
                        + "  " +(mDateTimePicker.getHour()<=9? String.valueOf("0"+mDateTimePicker.getHour()) : String.valueOf(mDateTimePicker.getHour())) + ":" + (mDateTimePicker.getMinute()<=9?String.valueOf("0"+mDateTimePicker.getMinute()):String.valueOf(mDateTimePicker.getMinute()))+" "+mDateTimePicker.getMeridiem();
                        editText.setText(result_string);
                        mDateTimeDialog.dismiss();
                    }
                });
                // Cancel the dialog when the "Cancel" button is clicked
                ((Button) mDateTimeDialogView.findViewById(R.id.CancelDialog)).setOnClickListener(new OnClickListener() {
                    public void onClick(View v) {
                        // TODO Auto-generated method stub
                        mDateTimeDialog.cancel();
                    }
                });
                // Reset Date and Time pickers when the "Reset" button is clicked
                ((Button) mDateTimeDialogView.findViewById(R.id.ResetDateTime)).setOnClickListener(new OnClickListener() {
                    public void onClick(View v) {
                        // TODO Auto-generated method stub
                        mDateTimePicker.reset();
                    }
                });

                // Setup TimePicker
                // No title on the dialog window
                mDateTimeDialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
                // Set the dialog content view
                mDateTimeDialog.setContentView(mDateTimeDialogView);
                // Display the dialog
                mDateTimeDialog.show();
            }
        });
    }
}

#5樓

個人自定義列表但願它說明概念

public class second extends ListActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.second);
//  TextView textview=(TextView)findViewById(R.id.textView1);
//  textview.setText(getIntent().getExtras().getString("value"));

    setListAdapter(new MyAdapter(this,R.layout.list_item,R.id.textView1, getResources().getStringArray(R.array.counteries)));
}

private class MyAdapter extends ArrayAdapter<String>{

    public MyAdapter(Context context, int resource, int textViewResourceId,
            String[] objects) {
        super(context, resource, textViewResourceId, objects);
        // TODO Auto-generated constructor stub
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        LayoutInflater inflater=(LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View row=inflater.inflate(R.layout.list_item,parent,false);
        String[]items=getResources().getStringArray(R.array.counteries);

        ImageView iv=(ImageView) row.findViewById(R.id.imageView1);
        TextView tv=(TextView) row.findViewById(R.id.textView1);
        tv.setText(items[position]);

        if(items[position].equals("unitedstates")){
            iv.setImageResource(R.drawable.usa);
        }else   if(items[position].equals("Russia")){
            iv.setImageResource(R.drawable.russia);
        }else   if(items[position].equals("Japan")){
            iv.setImageResource(R.drawable.japan);
        }
        // TODO Auto-generated method stub
        return row;
    }

}

}

相關標籤/搜索

每日一句

每一个你不满意的现在，都有一个你没有努力的曾经。