【问题标题】:How to pass data from Activity to DialogFragment如何将数据从 Activity 传递到 DialogFragment
【发布时间】:2017-06-21 21:17:53
【问题描述】:

我知道有一些关于如何将数据从活动传递到对话框(即捆绑或意图)的示例。但是,我尝试过的一切都不起作用。我不断收到 NPE 和 "Unable to find explicit activity class" 错误。即使我用对话框构建了一个超基本的活动,它也不起作用。我必须在代码中添加什么才能使其工作?

主活动:

public class MainActivity extends AppCompatActivity {

  Button button;
  String textIWantToSee;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    button = (Button) findViewById(R.id.button);

    textIWantToSee = "If this is the text I want to pass form this activity to the Fragment";

    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {


        }
    });
  }
}

对话框:

public class Dialog extends DialogFragment {

  TextView textView;

  @Override
  public android.app.Dialog onCreateDialog(Bundle savedInstanceState) {

    LayoutInflater inflater = getActivity().getLayoutInflater();
    View v = inflater.inflate(R.layout.dialog_layout, null);

    textView = (TextView) v.findViewById(R.id.textView);

    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
    builder.setView(v);

    return builder.create();
  }
}

更新

主活动:

public class MainActivity extends AppCompatActivity {

TextView tvIntent;
Button button;
String textIWantToSee;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    tvIntent = (TextView) findViewById(R.id.tvIntent);
    button = (Button) findViewById(R.id.button);

    textIWantToSee = "If this is the text I want to pass form this activity to the Fragment";
    tvIntent.setText(textIWantToSee);

    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            String intent = String.valueOf(tvIntent);
            Intent intentToDialog = new Intent(MainActivity.this, Dialog.class);
            intentToDialog.putExtra("keyForIntent", intent);
            startActivity(intentToDialog); //Here is the exception

        }
    });
}

} 对话框:

public class Dialog extends DialogFragment {

TextView textView;
String intent;

@Override
public android.app.Dialog onCreateDialog(Bundle savedInstanceState) {

    LayoutInflater inflater = getActivity().getLayoutInflater();
    View v = inflater.inflate(R.layout.dialog_layout, null);

    textView = (TextView) v.findViewById(R.id.textView);
    Intent intentFromDialog = new Intent(getActivity().getApplicationContext(),MainActivity.class);
    intent = intentFromDialog.getStringExtra("keyForIntent");
    textView.setText(intent);

    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
    builder.setView(v);

    return builder.create();
}

}

E/AndroidRuntime: FATAL EXCEPTION: main
              Process: nl.blogvandetoekomst.passdatafromactivitytodialog, PID: 2947
              android.content.ActivityNotFoundException: Unable to find explicit activity class {nl.blogvandetoekomst.passdatafromactivitytodialog/nl.blogvandetoekomst.passdatafromactivitytodialog.Dialog}; have you declared this activity in your AndroidManifest.xml?
                  at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1794)
                  at android.app.Instrumentation.execStartActivity(Instrumentation.java:1512)
                  at android.app.Activity.startActivityForResult(Activity.java:3917)
                  at android.app.Activity.startActivityForResult(Activity.java:3877)
                  at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:842)
                  at android.app.Activity.startActivity(Activity.java:4200)
                  at android.app.Activity.startActivity(Activity.java:4168)
                  at nl.blogvandetoekomst.passdatafromactivitytodialog.MainActivity$1.onClick(MainActivity.java:36)
                  at android.view.View.performClick(View.java:5198)
                  at android.view.View$PerformClick.run(View.java:21147)
                  at android.os.Handler.handleCallback(Handler.java:739)
                  at android.os.Handler.dispatchMessage(Handler.java:95)
                  at android.os.Looper.loop(Looper.java:148)
                  at android.app.ActivityThread.main(ActivityThread.java:5417)
                  at java.lang.reflect.Method.invoke(Native Method)
                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

清单:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="nl.blogvandetoekomst.passdatafromactivitytodialog">

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

【问题讨论】:

  • 请问,您的活动名称是什么?
  • 我有两个类: 1. MainActivity; 2. 对话框。
  • @AndroidRuntimeException:我知道还有其他例子。但关键是我无法让它工作,即使在像上面这样的超级基本程序中也是如此。我不明白我必须把那段代码放在哪里而不会出现“无法解析方法”等错误。
  • 您是否在清单中定义了活动?请添加堆栈跟踪错误。

标签: java android android-activity nullpointerexception android-dialogfragment


【解决方案1】:

这是您将数据从 Activity 传递到 DialogFragment 的方式:

MainActivity.java

public class MainActivity extends AppCompatActivity {

Button button;
String textIWantToSee;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    button = (Button) findViewById(R.id.button);

    textIWantToSee = "If this is the text I want to pass form this activity to the Fragment";

    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            Dialog dialogFragment = new Dialog();
            Bundle bundle = new Bundle();
            bundle.putString("TEXT",textIWantToSee);
            dialogFragment.setArguments(bundle);
            dialogFragment.show((MainActivity.this).getSupportFragmentManager(),"Image Dialog");

        }
    });
}
}

Dialog.java

public class Dialog extends DialogFragment {

TextView textView;

@Override
public android.app.Dialog onCreateDialog(Bundle savedInstanceState) {

    LayoutInflater inflater = getActivity().getLayoutInflater();
    View v = inflater.inflate(R.layout.dialog_layout, null);

    Bundle bundle = getArguments();
    String imageLink = bundle.getString("TEXT","");

    textView = (TextView) v.findViewById(R.id.textView);

    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
    builder.setView(v);

    return builder.create();
}
}

【讨论】:

  • 这给了我“无法解析方法 'show(android.support.v4.app.FragmentManager, java.lang.String)'”在 ((MainActivity.this).getSupportFragmentManager(),"Image对话框");
  • 你用的是哪个片段,是片段还是v4片段?
  • 'android.support.v7.app.AlertDialog;'是进口的。我导入了'android.support.v4.app.FragmentManager;'手动,但那个保持灰色。
【解决方案2】:

您的对话框片段需要一个托管 Activity,它需要在 Activity 中进行充气。

要在 MainActivity 中膨胀/显示 DialogFragment,请使用:

button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        Bundle bundle = new Bundle(); //Bundle containing data you are passing to the dialog
        bundle.putString("text", textIWantToSee);

        Dialog dialog = new Dialog(); //Create a new Dialog
        dialog.setArguments(bundle);

        dialog.show(getSupportFragmentManager(), "MY_DIALOG_TAG"); //Inflate the dialog
    }
});

【讨论】:

    【解决方案3】:

    如果您使用支持库,则应使用 android.support.v4.app.DialogFragment 而不是 android.app.Dialog。另外,您能否发布您用于显示对话框的部分代码?

    那么您必须使用 DialogFragment 的框架版本,正如 OBX 所指出的:

    MainActivity.java

    public class MainActivity extends AppCompatActivity {
    
        Button button;
        String textIWantToSee;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
            button = (Button) findViewById(R.id.button); 
    
            textIWantToSee = "If this is the text I want to pass form this activity to the Fragment";
    
            button.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
    
                    Dialog dialogFragment = new Dialog();
                    Bundle bundle = new Bundle();
                    bundle.putString("TEXT",textIWantToSee);
                    dialogFragment.setArguments(bundle);
                    dialogFragment.show(getFragmentManager(),"Image Dialog");
                }
            });
        }
    }
    

    Dialog.java

    public class Dialog extends DialogFragment {
    
        TextView textView;
    
        @Override
        public android.app.Dialog onCreateDialog(Bundle savedInstanceState) {
    
            LayoutInflater inflater = getActivity().getLayoutInflater();
            View v = inflater.inflate(R.layout.dialog_layout, null);
    
            Bundle bundle = getArguments();
            String imageLink = bundle.getString("TEXT","");
    
            textView = (TextView) v.findViewById(R.id.textView);
    
            AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
            builder.setView(v);
            return builder.create();
        }
    }
    

    这种方式对我来说非常有效。

    已编辑:

    当您在 onClick 中执行此操作时:

    Intent intentToDialog = new Intent(MainActivity.this, Dialog.class);
    intentToDialog.putExtra("keyForIntent", intent);
    startActivity(intentToDialog); //Here is the exception
    

    您没有启动 Activity,Dialog.class 是扩展的 DialogFragment,您无法显示启动 Activity 的对话框。试试我发布的最后一个代码。

    【讨论】:

    • 当我手动导入时“import android.support.v4.app.FragmentManager;”保持灰色。我没有显示对话框的特定代码。我尝试了 Bundle 和 Intent。类似于:“startActivity(intentToDialog);”和 "new Dialog().show(getFragmentManager(),"dialog");.
    【解决方案4】:

    使用 Dialog 片段的 newInstance。 参考:https://developer.android.com/reference/android/app/DialogFragment.html

       static MyDialogFragment newInstance(int num) {
        MyDialogFragment f = new MyDialogFragment();
    
        // Supply num input as an argument.
        Bundle args = new Bundle();
        args.putInt("num", num);
        f.setArguments(args);
    
        return f;
    }
    

    如果您使用的是 kotlin,请尝试在伴随对象中定义 newInstance

    companion object {
            fun newInstance(num: Int): MyDialogFragment{
                val f = DimensionDialogFragment()
                val args = Bundle()
                args.putInt("num", num)
                f.setArguments(args)
    
                return f
            }
        }
    

    【讨论】:

    • OP 说如何将数据从“Activity”传递到 DialogFragment 而不是 FragmentActivity 到 DialogActivity。
    【解决方案5】:

    您可以直接在 Activity 中创建对话框:

    button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
            LayoutInflater inflater = MainActivity.this.getLayoutInflater();
            View v = inflater.inflate(R.layout.dialog_layout, null);
    
            TextView textView = (TextView) v.findViewById(R.id.textView);
            textView.setText(textIWantToSee);
    
            AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
            builder.setView(v);
            builder.show();
    
            }
        });
    

    【讨论】:

    • 这是一个糟糕的方法,原因显而易见,DialogFragment 是推荐的方法
    • 这给了我“无法解析方法'getLayoutInflater()'”,“变量'v'已在范围内定义”,并且无法将Builder中的Builder(android.content.Context)应用于(匿名 android.view.View.OnClickListener)。
    • 你的活动名称是什么?
    • 我有两个类: 1. MainActivity; 2. 对话框。
    • 当我在= inflateretc 前面更改View v 时它可以工作。对于myVariable 它有效,因为v is already defined in the scope。非常感谢!
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