单击 ImageView 时，我无法将值附加到字符串

Question

I am trying to create a string whose content is dependent on the images clicked in an activity.

So, if Image1 is clicked, a given word is appended to the string, if Image2 is clicked, a second different word is appended to the string and so on.

Then, once all (or some) of the ImageViews are clicked, I would like to use trhis string as text to be sent through the SHARE INTENT.

So far so good: all images have been identified, same for the button, the append method is working fine, but when I try to share the string via e-mail or SMS, the text is absolutely empty.

Any idea why?

This is my MainActivity

public class MainActivity extends AppCompatActivity {

Button button;
String result ="";

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    button = (Button) findViewById(R.id.button);
    final int value1 = 300;
    final double value2 = 3.14;
    final short value3 = 5;
    final char value4 = 'A';


    // Create StringBuilder and add four values to it.
    final StringBuilder builder = new StringBuilder();


    ImageView imageview = (ImageView) findViewById(R.id.imageView);
    imageview.setOnClickListener(new View.OnClickListener() {

        @Override

        public void onClick(View v) {
            builder.append(value1).append("\n");
        }
    });

    ImageView imageview2 = (ImageView) findViewById(R.id.imageView2);
    imageview2.setOnClickListener(new View.OnClickListener() {

        @Override

        public void onClick(View v) {
            builder.append(value2).append("\n");
        }
    });

    result = builder.toString();


    Button button = (Button) findViewById(R.id.button);
    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            //create the send intent
            Intent shareIntent =
                    new Intent(Intent.ACTION_SEND);

            shareIntent.setType("text/plain");

            shareIntent.putExtra(Intent.EXTRA_SUBJECT,
                    "Insert Subject Here");

            String shareMessage = result;

            shareIntent.putExtra(Intent.EXTRA_TEXT,
                    shareMessage);

            startActivity(Intent.createChooser(shareIntent, "Share via"));
        }
    });
    }
}

as you can see, the text to be shared is the string "result" which should be composed of the text appended to it.

In my layout I have simply two ImageViews with a button. (clickable=true)

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

<ImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/imageView"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_marginTop="88dp"
    android:clickable="true"
    android:background="@mipmap/ic_launcher"
    android:contextClickable="true" />

<ImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/imageView2"
    android:clickable="true"
    android:background="@mipmap/ic_launcher"
    android:layout_alignTop="@+id/imageView"
    android:layout_alignRight="@+id/button"
    android:layout_alignEnd="@+id/button"
    android:contextClickable="true" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Share"
    android:id="@+id/button"
    android:layout_alignParentBottom="true"
    android:layout_alignParentRight="true"
    android:layout_alignParentEnd="true"
    android:clickable="true"
    android:contextClickable="true" />


</RelativeLayout>

Any idea??

Answer 1

To get appended value from StringBuffer . move :

result = builder.toString();

inside onClick of Button.

Problem is occurring because builder.toString() line is executed when onCreate method is called and values in StringBuffer is appending on click of ImageView's.