android中彈框很多種，alert框，dialog,AlertDialog,popupwindow,DialogFragment,toast，dialog樣式的activity等等，今天講解AlertDialog的簡單使用。

1 AlertDialog.Builder 設定相關引數

圖示，title，message，按鈕，是否點選消失等等。

 public void showDialog(){
        ImageView imageView = new ImageView(MainActivity.this);
        imageView.setImageResource
 
(R.mipmap.ic_launcher);
        final AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
        //title上的圖示和文字
        builder.setIcon(R.mipmap.ic_launcher);
        builder.setTitle("發現新版本");
        //自定義的title
        //builder.setCustomTitle(imageView);
        //dialog中間顯示的資訊
      //  builder.setMessage("Message");
 


        //設定是否可以取消
        builder.setCancelable(false);

        //Set a custom view resource to be the contents of the Dialog
        //不是全部view，只是message下的contents
        //builder.setView(R.layout.activity_main);

        builder.setItems(new String[]{"aaaa", "bbbbb", "cccc"}, new DialogInterface.OnClickListener
 
() {
            @Override
            public void onClick(DialogInterface dialog, int which) {

            }
        });

        //多選，單選item
       // builder.setMultiChoiceItems();
       // builder.setSingleChoiceItems();
        //確認按鈕
        builder.setPositiveButton(
                "立即更新",
                new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                    }
                });

        //取消按鈕
        builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();
            }
        });


        //具體位置和程式碼載入順序無關，跟樣式有關
        builder.setNeutralButton("其他",new DialogInterface.OnClickListener(){

            @Override
            public void onClick(DialogInterface dialog, int which) {

            }
        });

        AlertDialog dialog = builder.create();
        dialog.show();

    }

        final AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
        //title上的圖示和文字
        builder.setIcon(R.mipmap.ic_launcher);
        builder.setTitle("發現新版本");
        //dialog中間顯示的資訊
        builder.setMessage("Message");

        //設定是否可以取消
        builder.setCancelable(false);

        //Set a custom view resource to be the contents of the Dialog
        //不是全部view，只是message下的contents
        builder.setView(R.layout.activity_main);
        //確認按鈕
        builder.setPositiveButton(
                "立即更新",
                new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                    }
                });

        //取消按鈕
        builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();
            }
        });
        AlertDialog dialog = builder.create();
        dialog.show();

如果只想顯示按鈕，不錯任何操作：
builder.setNegativeButton(“取消”,null);

//點選外部是否消失
setCanceledOnTouchOutside( false );

2 dialog 設定（字型大小，顏色設定）

dialog.show之後，依然可以進行dialog的設定。

  AlertDialog dialog = builder.create();
        dialog.show();

        // 必須在執行show之後才能來設定
        TextView tvMsg = (TextView) dialog.findViewById(android.R.id.message);
        tvMsg.setTextSize(16);
        tvMsg.setTextColor(Color.RED);

        //設定按鈕的字型，顏色
        dialog.getButton(dialog.BUTTON_NEGATIVE).setTextSize(17);
        dialog.getButton(dialog.BUTTON_NEGATIVE).setTextColor(Color.BLUE);
        dialog.getButton(dialog.BUTTON_POSITIVE).setTextSize(17);
        dialog.getButton(dialog.BUTTON_POSITIVE).setTextColor(Color.BLACK);

設定自定義view：

  AlertDialog dialog = builder.create();
        dialog.show();
        dialog.setContentView(R.layout.activity_main);
        TextView textView = dialog.findViewById(R.id.idtv);
        textView.setText("sldfjslfjlsfjsf");
        textView.setTextColor(Color.RED);

原始碼解釋：

 /**
     * Set the screen content from a layout resource.  The resource will be
     * inflated, adding all top-level views to the screen.
     * 
     * @param layoutResID Resource ID to be inflated.
     */
    public void setContentView(@LayoutRes int layoutResID) {
        mWindow.setContentView(layoutResID);
    }

dialog重新獲取事件，進行更新：

  dialog.getButton(dialog.BUTTON_NEGATIVE).setOnClickListener(new View.OnClickListener() {
           @Override
           public void onClick(View v) {
               
           }
       });

設定背景：
dialog.getWindow().setBackgroundDrawable( new ColorDrawable( 0 ) );