Android中使用DialogFragment 創(chuàng)建對(duì)話框
DialogFragment在android 3.0時(shí)被引入。是一種特殊的Fragment，用于在Activity的內(nèi)容之上展示一個(gè)模態(tài)的對(duì)話框。典型的用于：展示警告框，輸入框，確認(rèn)框等等。
在DialogFragment產(chǎn)生之前，我們創(chuàng)建對(duì)話框：一般采用AlertDialog和Dialog。注：官方不推薦直接使用Dialog創(chuàng)建對(duì)話框。
2、 好處與用法
使用DialogFragment來(lái)管理對(duì)話框，當(dāng)旋轉(zhuǎn)屏幕和按下后退鍵時(shí)可以更好的管理其聲明周期，它和Fragment有著基本一致的聲明周期。且DialogFragment也允許開發(fā)者把Dialog作為內(nèi)嵌的組件進(jìn)行重用，類似Fragment（可以在大屏幕和小屏幕顯示出不同的效果）。上面會(huì)通過(guò)例子展示這些好處~
使用DialogFragment至少需要實(shí)現(xiàn)onCreateView或者onCreateDIalog方法。onCreateView即使用定義的xml布局文件展示Dialog。onCreateDialog即利用AlertDialog或者Dialog創(chuàng)建出Dialog。
3、 重寫onCreateView創(chuàng)建Dialog
a)布局文件，我們創(chuàng)建一個(gè)設(shè)置名稱的布局文件：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
<TextView
android:id="@+id/id_label_your_name"
android:layout_width="wrap_content"
android:layout_height="32dp"
android:gravity="center_vertical"
android:text="Your name:" />
<EditText
android:id="@+id/id_txt_your_name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_toRightOf="@id/id_label_your_name"
android:imeOptions="actionDone"
android:inputType="text" />
<Button
android:id="@+id/id_sure_edit_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_below="@id/id_txt_your_name"
android:text="ok" />
</RelativeLayout>
b)繼承DialogFragment，重寫onCreateView方法
package com.example.zhy_dialogfragment;
import android.app.DialogFragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class EditNameDialogFragment extends DialogFragment
{
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
{
View view = inflater.inflate(R.layout.fragment_edit_name, container);
return view;
}
}
c)測(cè)試運(yùn)行：
Main方法中調(diào)用：
效果圖：public void showEditDialog(View view)
{
EditNameDialogFragment editNameDialog = new EditNameDialogFragment();
editNameDialog.show(getFragmentManager(), "EditNameDialog");
}
可以看到，對(duì)話框成功創(chuàng)建并顯示出來(lái)，不過(guò)默認(rèn)對(duì)話框有個(gè)討厭的標(biāo)題，我們?cè)趺慈サ裟兀嚎梢栽趏nCreateView中調(diào)用getDialog().requestWindowFeature(Window.FEATURE_NO_TITLE);即可去掉。即：
public class EditNameDialogFragment extends DialogFragment
{
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
{
getDialog().requestWindowFeature(Window.FEATURE_NO_TITLE);
View view = inflater.inflate(R.layout.fragment_edit_name, container);
return view;
}
}
4、 重寫onCreateDialog創(chuàng)建Dialog
在onCreateDialog中一般可以使用AlertDialog或者Dialog創(chuàng)建對(duì)話框，不過(guò)既然google不推薦直接使用Dialog，我們就使用AlertDialog來(lái)創(chuàng)建一個(gè)登錄的對(duì)話框。
a)布局文件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical" >
<ImageView
android:layout_width="match_parent"
android:layout_height="64dp"
android:background="#FFFFBB33"
android:contentDescription="@string/app_name"
android:scaleType="center"
android:src="@drawable/title" />
<EditText
android:id="@+id/id_txt_username"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="4dp"
android:layout_marginLeft="4dp"
android:layout_marginRight="4dp"
android:layout_marginTop="16dp"
android:hint="input username"
android:inputType="textEmailAddress" />
<EditText
android:id="@+id/id_txt_password"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="16dp"
android:layout_marginLeft="4dp"
android:layout_marginRight="4dp"
android:layout_marginTop="4dp"
android:fontFamily="sans-serif"
android:hint="input password"
android:inputType="textPassword" />
</LinearLayout>
b)繼承DialogFragment重寫onCreateDialog方法
package com.example.zhy_dialogfragment;
import android.app.AlertDialog;
import android.app.Dialog;
import android.app.DialogFragment;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.EditText;
public class LoginDialogFragment extends DialogFragment
{
@Override
public Dialog onCreateDialog(Bundle savedInstanceState)
{
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
// Get the layout inflater
LayoutInflater inflater = getActivity().getLayoutInflater();
View view = inflater.inflate(R.layout.fragment_login_dialog, null);
// Inflate and set the layout for the dialog
// Pass null as the parent view because its going in the dialog layout
builder.setView(view)
// Add action buttons
.setPositiveButton("Sign in",
new DialogInterface.OnClickListener()
{
@Override
public void onClick(DialogInterface dialog, int id)
{
}
}).setNegativeButton("Cancel", null);
return builder.create();
}
}
c)調(diào)用
效果圖：public void showLoginDialog(View view)
{
LoginDialogFragment dialog = new LoginDialogFragment();
dialog.show(getFragmentManager(), "loginDialog");
}
可以看到通過(guò)重寫onCreateDialog同樣可以實(shí)現(xiàn)創(chuàng)建對(duì)話框，效果還是很nice的。
5、傳遞數(shù)據(jù)給Activity
從dialog傳遞數(shù)據(jù)給Activity，可以使用“fragment interface pattern”的方式，下面通過(guò)一個(gè)改造上面的登錄框來(lái)展示這種模式。
改動(dòng)比較小，直接貼代碼了：
package com.example.zhy_dialogfragment;
import android.app.AlertDialog;
import android.app.Dialog;
import android.app.DialogFragment;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.EditText;
public class LoginDialogFragment extends DialogFragment
{
private EditText mUsername;
private EditText mPassword;
public interface LoginInputListener
{
void onLoginInputComplete(String username, String password);
}
@Override
public Dialog onCreateDialog(Bundle savedInstanceState)
{
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
// Get the layout inflater
LayoutInflater inflater = getActivity().getLayoutInflater();
View view = inflater.inflate(R.layout.fragment_login_dialog, null);
mUsername = (EditText) view.findViewById(R.id.id_txt_username);
mPassword = (EditText) view.findViewById(R.id.id_txt_password);
// Inflate and set the layout for the dialog
// Pass null as the parent view because its going in the dialog layout
builder.setView(view)
// Add action buttons
.setPositiveButton("Sign in",
new DialogInterface.OnClickListener()
{
@Override
public void onClick(DialogInterface dialog, int id)
{
LoginInputListener listener = (LoginInputListener) getActivity();
listener.onLoginInputComplete(mUsername
.getText().toString(), mPassword
.getText().toString());
}
}).setNegativeButton("Cancel", null);
return builder.create();
}
}
拿到username和password的引用，在點(diǎn)擊登錄的時(shí)候，把a(bǔ)ctivity強(qiáng)轉(zhuǎn)為我們自定義的接口：LoginInputListener，然后將用戶輸入的數(shù)據(jù)返回。
MainActivity中需要實(shí)現(xiàn)我們的接口LoginInputListener，實(shí)現(xiàn)我們的方法，就可以實(shí)現(xiàn)當(dāng)用戶點(diǎn)擊登陸時(shí)，獲得我們的帳號(hào)密碼了：
c) MainActivity
package com.example.zhy_dialogfragment;
import com.example.zhy_dialogfragment.LoginDialogFragment.LoginInputListener;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Toast;
public class MainActivity extends Activity implements LoginInputListener
{
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void showLoginDialog(View view)
{
LoginDialogFragment dialog = new LoginDialogFragment();
dialog.show(getFragmentManager(), "loginDialog");
}
@Override
public void onLoginInputComplete(String username, String password)
{
Toast.makeText(this, "帳號(hào)：" + username + ", 密碼 :" + password,
Toast.LENGTH_SHORT).show();
}
}
效果：
6、DialogFragment做屏幕適配
我們希望，一個(gè)對(duì)話框在大屏幕上以對(duì)話框的形式展示，而小屏幕上則直接嵌入當(dāng)前的Actvity中。這種效果的對(duì)話框，只能通過(guò)重寫onCreateView實(shí)現(xiàn)。下面我們利用上面的EditNameDialogFragment來(lái)顯示。
EditNameDialogFragment我們已經(jīng)編寫好了，直接在MainActivity中寫調(diào)用
public void showDialogInDifferentScreen(View view)
{
FragmentManager fragmentManager = getFragmentManager();
EditNameDialogFragment newFragment = new EditNameDialogFragment();
boolean mIsLargeLayout = getResources().getBoolean(R.bool.large_layout) ;
Log.e("TAG", mIsLargeLayout+"");
if (mIsLargeLayout )
{
// The device is using a large layout, so show the fragment as a
// dialog
newFragment.show(fragmentManager, "dialog");
} else
{
// The device is smaller, so show the fragment fullscreen
FragmentTransaction transaction = fragmentManager
.beginTransaction();
// For a little polish, specify a transition animation
transaction
.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
// To make it fullscreen, use the 'content' root view as the
// container
// for the fragment, which is always the root view for the activity
transaction.replace(R.id.id_ly, newFragment)
.commit();
}
}
可以看到，我們通過(guò)讀取R.bool.large_layout，然后根據(jù)得到的布爾值，如果是大屏幕則直接以對(duì)話框顯示，如果是小屏幕則嵌入我們的Activity布局中
這個(gè)R.bool.large_layout是我們定義的資源文件：
在默認(rèn)的values下新建一個(gè)bools.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<bool name="large_layout">false</bool>
</resources>
然后在res下新建一個(gè)values-large，在values-large下再新建一個(gè)bools.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<bool name="large_layout">true</bool>
</resources>
最后測(cè)試：
左邊為模擬器，右邊為我的手機(jī)~~~~~
7、屏幕旋轉(zhuǎn)
當(dāng)用戶輸入帳號(hào)密碼時(shí)，忽然旋轉(zhuǎn)了一下屏幕，帳號(hào)密碼不見了~~~是不是會(huì)抓狂
傳統(tǒng)的new AlertDialog在屏幕旋轉(zhuǎn)時(shí)，第一不會(huì)保存用戶輸入的值，第二還會(huì)報(bào)異常，因?yàn)锳ctivity銷毀前不允許對(duì)話框未關(guān)閉。而通過(guò)DialogFragment實(shí)現(xiàn)的對(duì)話框則可以完全不必考慮旋轉(zhuǎn)的問題。
我們直接把上面登錄使用AlertDialog創(chuàng)建的登錄框，拷貝到MainActivity中直接調(diào)用：
public void showLoginDialogWithoutFragment(View view)
{
AlertDialog.Builder builder = new AlertDialog.Builder(this);
// Get the layout inflater
LayoutInflater inflater = this.getLayoutInflater();
// Inflate and set the layout for the dialog
// Pass null as the parent view because its going in the dialog layout
builder.setView(inflater.inflate(R.layout.fragment_login_dialog, null))
// Add action buttons
.setPositiveButton("Sign in",
new DialogInterface.OnClickListener()
{
@Override
public void onClick(DialogInterface dialog, int id)
{
// sign in the user ...
}
}).setNegativeButton("Cancel", null).show();
}
下面我分別點(diǎn)擊兩種方式創(chuàng)建的登錄框，看效果圖：
可以看到，傳統(tǒng)的Dialog旋轉(zhuǎn)屏幕時(shí)就消失了，且后臺(tái)log會(huì)報(bào)異常~~~使用DialogFragment則不受影響。
好了，關(guān)于DialogFragment的介紹結(jié)束~~~~
有任何疑問請(qǐng)留言
參考文檔：
http://developer.android.com/guide/topics/ui/dialogs.html#DialogFragment
https://github.com/thecodepath/android_guides/wiki/Using-DialogFragment
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