DialogFragment对话框(二) ——Fragment和Activity的通信

fragment 通信 dialog android
作者：陈小默

紧接着上一节，DialogFragment对话框(一) ——创建对话框，这里通过在DialogFragment对话框回传EditText中的数据来介绍几种Fragment和Activity之间通信的方法

准备工作，修改上一节中的布局文件，将TextView换成EditText
dialog_view.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    <EditText
        android:id="@+id/message"
        android:layout_width="300dp"
        android:layout_height="wrap_content" />
    <Button
        android:id="@+id/ok"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="确定" />
</LinearLayout>

接口回调

最古老也是最原始的通信方式
定义一个作为回调的接口
Callback.kt

interface Callback {
    fun response(message:String)
}

在Activity中传递回调接口参数

    private fun showViewDialog() {
        var dialog: MyViewDialogFragment = MyViewDialogFragment()
        var bundle = Bundle()
        bundle.putSerializable("callback", object : Callback {
            override fun response(message: String) {
                Toast.makeText(this@ShowActivity, message, Toast.LENGTH_SHORT).show()
            }
        })
        dialog.arguments=bundle
        dialog.show(fragmentManager, "tag")
    }

在Fragment中接收参数

class MyViewDialogFragment : DialogFragment() {
    private var callback: Callback? = null
    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
        dialog.requestWindowFeature(Window.FEATURE_NO_TITLE)//设置窗体为无标题
        callback = arguments["callback"] as Callback//获得Activity传来的回调接口
        var view: View = inflater.inflate(R.layout.dialog_view, container, false)
        initView(view)
        return view
    }
    override fun show(manager: FragmentManager?, tag: String?) {
        super.show(manager, tag)
    }
    private fun initView(view: View) {
        var message = view.findViewById(R.id.message) as EditText
        var button = view.findViewById(R.id.ok) as Button
        button.setOnClickListener { view ->
            callback?.response(message.text.toString())
            dismiss()
        }
    }
}

这时候再运行，我们就能看到Activity中吐司的对话框中输入的文字了

EventBus

使用EventBus传递数据应该是最简便的方法了
修改Activity的代码

class ShowActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_show)
        findViewById(R.id.alertDialog).setOnClickListener { view -> showAlertDialog() }
        findViewById(R.id.viewDialog).setOnClickListener { view -> showViewDialog() }
        EventBus.getDefault().register(this)
    }
    private fun showAlertDialog() {
        var dialog: MyAlertDialogFragment = MyAlertDialogFragment()
        dialog.ctx = this
        dialog.show(fragmentManager, "tag")
    }
    private fun showViewDialog() {
        var dialog: MyViewDialogFragment = MyViewDialogFragment()
        dialog.show(fragmentManager, "tag")
    }
    @Subscribe open fun response(message:String){
        Toast.makeText(this@ShowActivity, message, Toast.LENGTH_SHORT).show()
    }
    override fun onDestroy() {
        EventBus.getDefault().unregister(this)
        super.onDestroy()
    }
}

修改Fragment的代码

class MyViewDialogFragment : DialogFragment() {
    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
        dialog.requestWindowFeature(Window.FEATURE_NO_TITLE)//设置窗体为无标题
        var view: View = inflater.inflate(R.layout.dialog_view, container, false)
        initView(view)
        return view
    }
    override fun show(manager: FragmentManager?, tag: String?) {
        super.show(manager, tag)
    }
    private fun initView(view: View) {
        var message = view.findViewById(R.id.message) as EditText
        var button = view.findViewById(R.id.ok) as Button
        button.setOnClickListener { view ->
            EventBus.getDefault().post(message.text.toString())
            dismiss()
        }
    }
}