intent_tronglap_trinh_android_2_258.pdf

III-S dng Intent nh th no?

-Cc hm thc thi Activity

-Intent tng minh thc thi Activity

Nh trnh by phn II, intent c th dng thuc tnh ph component ch nh ch danh tn lp s thc thi Activity. thc hin iu ny, lp Intent cung cp cc hm l setComponent(ComponentName) v setClass(Context, Class) v setClassName(Context, String) setClassName(String, String).

Ch c dng gi cc Activities trong cng mt app

VD: PHP Code:

Intent intent = new Intent();

intent.setClassName("ten_package", "ten_lop_ben_tr

ong_package");

startActivity(intent);

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-Intent khng tng minh thc thi Activity

Trong trng hp ny intent khng ch nh mt lp c th m thay vo dng cc d liu khc (action, data, type, etc.) v h thng t quyt nh xem lp no (app no) s thch hp p ng intent .

Thng tin action v category ca activity trong mt app p ng intent phi c khai bo trong Manifest ca app (AndroidManifest.xml) di dng Intent-filter (tt nhin nu chng ta mun gi mt built-in action th ta khng cn quan tm n vn ny). VD: PHP Code:

IV-Truyn nhn thng tin gia cc Activity s dng intent

-Gi s ta xy dng mt app c hai activites A v B nh hnh v trn. Khi bn phi Activity A ta s gi hm: PHP Code:

startActivity(intentA,request_code)

-Bn pha Activity B ta s gi hm:

PHP Code:

setResult(return_code, intentB);

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Trong phn 1, mnh trnh by nhng kin thc c bn v Intent. Tip theo mnh s hng dn cc bn lm mt Tutorial n gin hiu r hn nhng vn nu trong l thuyt.

-Gi s bn cn vit mt app tnh cc phn t ca mt dy s c cho theo quy lut: PHP Code:

a0,b0 nhp t bn phm

a(n+1)=a(n)+b(n)

b(n+1)=a(n)*b(n)

thc hin, chng ta xy dng hai Activities 1 v 2. Activity 1 s lm nhim v ly d liu nhp vo sau gi Activity 2 tnh ton kt qu v ly d liu tr v. Ngi dng s quyt nh tip tc tnh ton hay reset li t u. Ton b qu trnh ny c minh ha nh hnh v di y:

-u tin bn to mt New Project nh sau: PHP Code:

Project Name: IntentBasic

Target: bt k (vd 1.5)

Package name: com.vietanddev.intent

Application name: Intent Basic

-Tip theo bn to layout cho hai Activities nh hnh v di

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input.xml PHP Code:

android:background="@android:drawable/editbox_backg

round"

android:layout_marginRight="10dip"

android:layout_toRightOf="@id/TextView02"

android:layout_alignBottom="@id/TextView02">

result.xml PHP Code:

android:text="A * B = "

android:layout_margin="10dip"

android:layout_height="wrap_content">

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