Android Dialog总结

Dialog是对话框的基类，在使用中应该避免直接实例化Dialog，可以用其子类AlertDialog。

官方规定使用 DialogFragment作为Dialog的容器,好处在于，当屏幕旋转或者用户点击返回键时，它可以帮助你管理生命周期，并且它可以根据屏幕尺寸大小和你的需要帮助你创建一个Dialog或者是一个全屏的Fragment。、

1.创建一个最简单的 AlertDialog

标准的AlertDialog包含3个部分：

1.标题Title

2.内容Content area

3.动作按钮Action buttons（Positive，Negative，Neutral）

public class AlertDialogFragment extends DialogFragment 
implements DialogInterface.OnClickListener
{
	public static AlertDialogFragment newInstance(String message)
	{
		AlertDialogFragment adf = new AlertDialogFragment();
		Bundle bundle = new Bundle();
		bundle.putString("alert-message", message);
		adf.setArguments(bundle);
		
		return adf;
	}

    @Override    
    public void onCreate(Bundle savedInstanceState)
    {
    	super.onCreate(savedInstanceState);
    	this.setCancelable(true);
        int style = DialogFragment.STYLE_NORMAL, theme = 0;
        setStyle(style,theme);
    }

    @Override    
    public Dialog onCreateDialog(Bundle savedInstanceState) 
    {        
    	AlertDialog.Builder b = 
    	    new AlertDialog.Builder(getActivity())
    	    .setTitle("Alert!!")
    	    .setPositiveButton("Ok", this)
    	    .setNegativeButton("Cancel", this)
    	    .setMessage(this.getArguments().getString("alert-message"));
    	return b.create();
    }

    public void onClick(DialogInterface dialog, int which)
    {
    }
}

显示对话框：

    	FragmentTransaction ft = 
    		getFragmentManager().beginTransaction();
    	
    	AlertDialogFragment adf = 
    		AlertDialogFragment.newInstance(
    				"Alert Message");
    	
    	adf.show(ft, "ALERT_DIALOG_TAG");

2.创建列表Dialog

    @Override    
    public Dialog onCreateDialog(Bundle savedInstanceState) 
    {        
    	AlertDialog.Builder b = 
    	    new AlertDialog.Builder(getActivity())
    	    .setTitle("Alert!!")
    	    .setPositiveButton("Ok", this)
    	    .setNegativeButton("Cancel", this)
    	    .setItems(new String[] {"a", "b", "c"}, new DialogInterface.OnClickListener() {

				@Override
				public void onClick(DialogInterface dialog, int which) {
					Toast.makeText(getActivity(), "点击了第"+ (which+1) +"项", Toast.LENGTH_SHORT).show();
				}
    	    });
    	return b.create();
    }

如果需要将动态数据作为列表项，可以使用setAdapter (ListAdapter adapter, DialogInterface.OnClickListener listener)

3.创建单选/多选Dialog

单选：

    @Override    
    public Dialog onCreateDialog(Bundle savedInstanceState) 
    {        
    	AlertDialog.Builder b = 
    	    new AlertDialog.Builder(getActivity())
    	    .setTitle("Alert!!")
    	    .setPositiveButton("Ok", this)
    	    .setNegativeButton("Cancel", this)
    	    .setSingleChoiceItems(new String[] {"a", "b", "c"}, -1, new DialogInterface.OnClickListener() {
				
				@Override
				public void onClick(DialogInterface dialog, int which) {
					
				}
			});
    	return b.create();
    }

多选：

    @Override    
    public Dialog onCreateDialog(Bundle savedInstanceState) 
    {        
    	AlertDialog.Builder b = 
    	    new AlertDialog.Builder(getActivity())
    	    .setTitle("Alert!!")
    	    .setPositiveButton("Ok", this)
    	    .setNegativeButton("Cancel", this)
    	    .setMultiChoiceItems(new String[] {"a", "b", "c"}, null, new DialogInterface.OnMultiChoiceClickListener() {

				@Override
				public void onClick(DialogInterface dialog, int which,
						boolean isChecked) {
				}
    	    	
    	    });
    	return b.create();
    }

4.自定义布局的Dialog

需要在onCreateView中加载自定义布局，再调用show显示。

public class HelpDialogFragment extends DialogFragment implements
		View.OnClickListener {
	public static HelpDialogFragment newInstance(int helpResId) {
		HelpDialogFragment hdf = new HelpDialogFragment();
		Bundle bundle = new Bundle();
		bundle.putInt("help_resource", helpResId);
		hdf.setArguments(bundle);

		return hdf;
	}

	@Override
	public void onCreate(Bundle icicle) {
		super.onCreate(icicle);
		this.setCancelable(true);
		int style = DialogFragment.STYLE_NORMAL, theme = 0;
		setStyle(style, theme);
	}

	public View onCreateView(LayoutInflater inflater, ViewGroup container,
			Bundle icicle) {
		View v = inflater.inflate(R.layout.help_dialog, container, false);

		TextView tv = (TextView) v.findViewById(R.id.helpmessage);
		tv.setText(getActivity().getResources().getText(
				getArguments().getInt("help_resource")));

		Button closeBtn = (Button) v.findViewById(R.id.btn_close);
		closeBtn.setOnClickListener(this);
		return v;
	}

	public void onClick(View v) {
		dismiss();
	}
}

布局：help_dialog：

显示：

    	FragmentTransaction ft = 
    		getFragmentManager().beginTransaction();
    	
    	HelpDialogFragment hdf = 
    		HelpDialogFragment.newInstance(
    			 R.string.help_text);
    	
    	hdf.show(ft, "HELP_DIALOG_TAG");

5.对话框的关联

可以通过Fragment的回退栈设置2个前后关联的Dialog：第一个Dialog点击按钮打开第二个Dialog，第二个Dialog按返回键重新显示第一个Dialog，这种逻辑在屏幕旋转时依然有效。

			FragmentTransaction ft = getFragmentManager().beginTransaction();
		    ft.remove(this);
		    
		    //加入回退栈
		    ft.addToBackStack(null);

		    HelpDialogFragment hdf =
		    	    HelpDialogFragment.newInstance(R.string.help1);
		    hdf.show(ft, MainActivity.HELP_DIALOG_TAG);

以上代码写在一个DIalog的Button中，点击Button，显示上面的HelpDialogFragment，再按返回键，退出HelpDialogFragment，显示刚才的Dialog。

6.对话框回调。

如果希望在点击Dialog后通知创建它的activity或者 fragment ，一种方法是直接在OnclickListener里面写逻辑，更通用的方法是，在DialogFragment内定义一个接口，为每个按钮的点击事件设置回调方法。这样一来，所有实现接口的activity或者 fragment都能在回调方法中处理按钮逻辑。

DialogFragment：

public class AlertDialogFragment extends DialogFragment {
	
	private NoticeDialogListener mListener;

	public interface NoticeDialogListener {
		public void onDialogPositiveClick(DialogFragment dialog);

		public void onDialogNegativeClick(DialogFragment dialog);
	}

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		this.setCancelable(true);
		int style = DialogFragment.STYLE_NORMAL, theme = 0;
		setStyle(style, theme);
	}
	
	@Override
	public void onAttach(Activity activity) {
		super.onAttach(activity);
		
		if (activity instanceof NoticeDialogListener) {
			mListener = (NoticeDialogListener) activity;
		}
		
	}

	@Override
	public Dialog onCreateDialog(Bundle savedInstanceState) {
		AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
		builder.setPositiveButton("ok", new DialogInterface.OnClickListener(){

			@Override
			public void onClick(DialogInterface dialog, int which) {
				if (mListener != null) {
					mListener.onDialogPositiveClick(AlertDialogFragment.this);
				}
			}
		}).setNegativeButton("cancel", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                mListener.onDialogNegativeClick(AlertDialogFragment.this);
            }
        });;
		
		return builder.create();
	}
}

Activity：

public class MainActivity extends Activity implements NoticeDialogListener
{
	……
	
    private void testAlertDialog()
    {
    	FragmentTransaction ft = 
    		getFragmentManager().beginTransaction();
    	
    	AlertDialogFragment adf = new AlertDialogFragment();
    	adf.show(ft, ALERT_DIALOG_TAG);
    	
    }
    
	@Override
	public void onDialogPositiveClick(DialogFragment dialog) {
		Toast.makeText(this, "点击了ok按钮", Toast.LENGTH_SHORT).show();
	}

	@Override
	public void onDialogNegativeClick(DialogFragment dialog) {
		Toast.makeText(this, "点击了cancel按钮", Toast.LENGTH_SHORT).show();
	}
	
	……
}

这是使用了设计模式中的观察者模式

7.onCancel,onDismiss

以下情况会调用DialogFragment的onCancel回调方法：

Dialog显示时，按返回键，回调方法调用过程：

onCancel-》onDismiss-》onDestroy

除了以上情况，以下情况会调用DialogFragment的onDismiss回调方法：

旋转屏幕，回调方法调用过程：onDestroy-》onDismiss

注：横竖屏切换时，DialogFragment会处理Dialog的生命周期，使其仍然显示在前台。