Change TextView text

Question

I'm trying to change my TextView text from the code.

This is what my xml looks like:

XML:
<TextView
    android:id="@+id/textView1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:gravity="center_vertical|center_horizontal" />

And the code:

TextView tv1 = (TextView)findViewById(R.id.textView1);
tv1.setText("Hello");
setContentView(tv1);

I'm getting an error on my device and the application stops. I tried to show a TextView (not connected to an XML TextView) and it worked.

TextView cannot be set as your parent view. You'll have to surround the TextView with a LinearLayout. — SamSPICA, Nov 19 '12 at 11:40
^ correct Show us your oncreate method, what's the name of your xml file? — Hades, Nov 19 '12 at 11:41

score 72 · Accepted Answer · edited Apr 03 '20 at 00:56

72

Your approach is incorrect. I think it will be Null Pointer Exception (next time post log cat)

You need to specify the layout you are using first, before finding views.

Java:

// Specify the layout you are using.
setContentView(R.layout.yourlayout);

// Load and use views afterwards
TextView tv1 = (TextView)findViewById(R.id.textView1);
tv1.setText("Hello");

Kotlin:

// Specify the layout you are using.
setContentView(R.layout.yourlayout)

// Load and use views afterwards
val tv1: TextView = findViewById(R.id.textView1)
tv1.text = "Hello"

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edited Apr 03 '20 at 00:56

ChrisMcJava

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answered Nov 19 '12 at 11:40

Abhi

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@ImriPersiado Then you can accept the answer,Just by tick mark which is at left side of my answer :P – Abhi Nov 19 '12 at 11:59
@ChrisMcJava - Shouldn't the Kotlin version using synthetic? – charles-allen Apr 03 '20 at 01:02
1

@AjahnCharles: Kotlinx synthetic is no longer recommended standard practice: https://android-review.googlesource.com/c/platform/frameworks/support/+/882241 Explanation from Android at Google: https://www.reddit.com/r/androiddev/comments/ala9p2/why_kotlinx_synthetic_is_no_longer_a_recommended/efdvpkg/ – ChrisMcJava Apr 03 '20 at 17:30

score 5 · Answer 2 · answered Nov 19 '12 at 11:40

5

remove this.. setContentView(tv1);

answered Nov 19 '12 at 11:40

Henrik

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score 3 · Answer 3 · answered Mar 27 '21 at 10:17

I got the same problem. My app was stopping too. Actually, I was writing the code outside of the function/method. So to fix this problem, these lines

TextView tv1 = (TextView)findViewById(R.id.textView1);
tv1.setText("Hello");

must be inside a function/method. (can be user defined) (I am new to android studio so I don't know the reason behind the problem but I only know how to fix this. Maybe this helps new ones despite this question being 8 years old.)

Change TextView text

3 Answers3

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